9/11 Physics from Non-Experts

[Totovader]

This is what happens when an incomplete education prevents someone from being able to scientifically understand something. I'm no physics expert, but it's painfully easy to see what mistakes he's making.

jYMDsBN3t80

It's actually quite hilarious that he just totally flips out because I asked him for his figures...

According to people like this- all impacts would simply cease because- as they claim- "the net force is zero". To the conspiracists, the buildings should have just stopped- and "calculations are unimportant".

Don't ever ride in a car with one of these people...

[WildCat]

This is what happens when an incomplete education prevents someone from being able to scientifically understand something. I'm no physics expert, but it's painfully easy to see what mistakes he's making.

jYMDsBN3t80

It's actually quite hilarious that he just totally flips out because I asked him for his figures...

According to people like this- all impacts would simply cease because- as they claim- "the net force is zero". To the conspiracists, the buildings should have just stopped- and "calculations are unimportant".

Don't ever ride in a car with one of these people...
"The ground pushes up", wow that's just stupid. :jaw-dropp

[crucial_fiction]

Oh man that's good stuff. I needed that laugh thanks!!

[~enigma~]

Let me raise a somewhat different point that these guys seem to be missing. Constant motion is a sign of NO external force entering the system. Last time I checked wasn't that an extremely basic principle of physics?

[slugmancs]

From the mouths of babes, luckily the accent indicates this is not a product of our failing education system.

[Horatius]

Well, he's certainly mastered the Alex Jones' School of Shouting Louder to Make Your Point!



Just another twoofer who doesn't understand the difference between a solid object, and one that is mostly empty, with a complex, interdependent structure. If they could just grasp that, they'd be much farther ahead.

[A W Smith]

what a waste of an otherwise perfectly good artists sketch pad.

[beachnut]

What? The ground pushes up? What force is that?

I modeled the collapse as a pancake with the momentum and force to destroy a floor. As each floor fails it gains momentum since the first momentum was more than enough to fail the first floor, and the mass continues to move down and accelerate with the new velocity modified by the total new mass minus any energy required to fail a floor. He should have run some numbers. He uses his four letter physics term to prove F=0. Someone could model the WTC number of upper floors required to start a global collapse once a failure occurs. On 9/11 the number would have been less than the floors above the first impact zone.

I like how he says the top would crush a few floors and stop. Which part of "if the first floor below the impact is crushed by the top floors the building is doomed" does he not understand. Even Ross's numbers show only 186 pounds of TNT equal energy are missing for global collapse to start, and since our new expert says a few floors would be crushed, he has even failed the Ross test.

Yes it is best if you do not ride with our force/momentum expert since he does not understand math, physics or energy. How long has this idiot been preaching to the PrisonPlanet super elite open minded scholars of false information and outright junk science?

[~enigma~]

What? The ground pushes up? What force is that? According to the flat earth society that is gravity :)

[stilicho]

In this individual's alternative earth it would be almost impossible to have a lumber industry. The damn trees would never fall over.

On the other hand, we probably wouldn't have to mine for coal or drill for oil either.

[T.A.M.]

In this individual's alternative earth it would be almost impossible to have a lumber industry. The damn trees would never fall over.

On the other hand, we probably wouldn't have to mine for coal or drill for oil either.

more accurately, in this imaginary world, the trees would fall, hit the ground, then bounce back up again...lol

TAM:)

[gumboot]

Wow... he's got bits of Australian, New Zealand, and South African accents...

He's not actual human at all, he's Darwin's Missing Link! Homo Antipodus!

-Gumboot

[jhunter1163]

more accurately, in this imaginary world, the trees would fall, hit the ground, then bounce back up again...lol

TAM:)

With a "sproinnnnnnng" sound no doubt.

[chran]

Why the hell is he shouting at me?!

Go put a shrimp on the barby, mate! Sheesh ...

[stilicho]

I just realised this new form of alternative physics would easily explain why the Pentagon light standards just 'popped out of the ground'. With the earth constantly pushing up like that, all sorts of things would pop out of the ground.

[LashL]

Humorous stuff, indeed. Just look at all that table thumping.

It's like a page out of Bad Lawyering 101:
When you have absolutely no legitimate argument to make whatsoever, raise your voice and thump the table repeatedly.

:D

[qarnos]

Wow... he's got bits of Australian, New Zealand, and South African accents...

He's not actual human at all, he's Darwin's Missing Link! Homo Antipodus!

-Gumboot

That had me dumbfounded too... I just can't pick his accent.

Oh I long for the days when I knew everything.

[qarnos]

"The ground pushes up", wow that's just stupid. :jaw-dropp

"If you don't understand basic Newtonian physics and basic thermodynamics then you'll not understand this". :wide-eyed

[gumboot]

I just realised this new form of alternative physics would easily explain why the Pentagon light standards just 'popped out of the ground'. With the earth constantly pushing up like that, all sorts of things would pop out of the ground.


He's also singlehandedly explained the living dead... :jaw-dropp

They're not reanimated, the ground is just pushing them back up.

-Gumboot

[Quad4_72]

Why is it so hard to grasp that the towers were not solid objects?

[Foolmewunz]

Why is it so hard to grasp that the towers were not solid objects?

But they were solid, I saw the sketch he drew and they sure looked solid to me.

I love that complete cut... just sliced the building stragiht through like a big block of Velveeta.

I'm glad I now know how to define a "force"..... gravity is a force..... and the uh, ground.... yeah, the ground holding....no, strike that... the ground pushing.... yeah that's it ..... The Ground Pushing Up is a force.

I missed that lecture in Physics - Groundpushingupital Forces and Their Relation to All Fall Down Go Boom

[gumboot]

"If you don't understand basic Newtonian physics and basic thermodynamics then you'll not understand this". :wide-eyed



That's true. Of course, if you do understand basic Newtonian physics and basic thermodynamics you also won't understand it.

-Gumboot

[Zep]

I'm guessing he's an immigrant to Australia from elsewhere, as a child.

And I think it proves conclusively that we, too, have ignorant morons.

[gumboot]

I'm guessing he's an immigrant to Australia from elsewhere, as a child.

And I think it proves conclusively that we, too, have ignorant morons.



Upon additional viewings I am almost certain he is a South African immigrant to Australia.

-Gumboot

[Shrinker]

"The ground pushes up", wow that's just stupid. :jaw-dropp

I don't understand. In school I was taught that when an object is at rest, say on a table, the table is supplying the upward force necessary to keep it there.

Other than being a simplification of forces at the molecular level, is that wrong?

[Gravy]

Caffeine + stupidity = truther comedy gold.

[Zep]

He's completely misunderstanding the "equal and opposite reaction" thing. And he has no idea about momentum either. And his notion that the WTC towers were somehow "solid", and that they should have defied gravity and toppled over somehow, indicates he hasn't a frigging clue what he is waffling on about.

What I would have liked to have seen would be a skeptic asking him questions about his "explanation" at the end, just to see if he would actually froth up and explode. ;) :)

[Shrinker]

Could somebody respond on Youtube to his "You coincidentalists can't win." post by pointing out that he seems to be 100% right, because his debate opponent "beefmadras" has been banned from posting.

[bje]

The poor chap may have attended Steven Jones's classes.

[Horatius]

He's completely misunderstanding the "equal and opposite reaction" thing.



That's just it. The "ground pushing up" line is his misunderstanding of the reaction force of the ground against the building. If the ground didn't equally and oppositely match the force of gravity in the building (when it was still sound), the building would still accelerate downwards. Fnet must be zero for the building to remain motionless. What he doesn't understand is, if there's no connection between the ground and the object, the reaction force no longer exists.

And of course, once the structural connection betwen the lower building and the upper building is lost (say, by whacking a plane into it), then there's no longer a reaction force on the upper portion, so it starts to fall. He seems to think that, once the moving upper part hits the lower part, the exactly equal reaction force will magically re-appear and stop the movement.

But of course, designing a complex building structure that can transfer reaction forces from the ground upwards, is an involved and precise process, and the chances of this happening "accidentally" as the building falls is so small as to not matter.

That's where he falls down.

[Totovader]

I linked part 2, here is part 1:

sbyu0zuxo5A

It's really bad. He's trying to explain physics- which he clearly doesn't understand.

[T.A.M.]

example #1...

African woman holds water vase atop her head.

example #2...

Take said vase, lift it 8-12 feet up from her head, then drop it.

DO I have to say more...

TAM:)

[Totovader]

Could somebody respond on Youtube to his "You coincidentalists can't win." post by pointing out that he seems to be 100% right, because his debate opponent "beefmadras" has been banned from posting.

He's blocked everyone from posting who doesn't agree with him. I've had most of my comments removed even after I reposted them- and then he blocked me as well. All I did was ask for his calculations.

I notice that someone got a shot off- they asked him if he had shown this to his professor, he said that his high school teacher agreed with him...

...

I find it hard to believe that the kid explained it to his high school teacher like he did on YouTube- but even if he had, this just emphasizes my point: an incomplete education is a very dangerous thing. By shutting out any disagreement- by not even questioning your conclusions- and by looking for confirming evidence, even if it means bastardizing science itself- we arrive at the core of conspiracy theories.

Unfortunately- these types of conspiracy theory claims are going to be more popular: the kids with little or no education trying to prove "physics was violated" like their bigger- and just as ignorant- counter-parts are doing: Jones, et al. It appeals to people grasping at straws and in some of these cases it takes a greater education to defeat the argument.

Although- I always fall back on logic.

[~enigma~]

He's blocked everyone from posting who doesn't agree with him. I've had most of my comments removed even after I reposted them- and then he blocked me as well. All I did was ask for his calculations.

I notice that someone got a shot off- they asked him if he had shown this to his professor, he said that his high school teacher agreed with him...

...

I find it hard to believe that the kid explained it to his high school teacher like he did on YouTube- but even if he had, this just emphasizes my point: an incomplete education is a very dangerous thing. By shutting out any disagreement- by not even questioning your conclusions- and by looking for confirming evidence, even if it means bastardizing science itself- we arrive at the core of conspiracy theories.

Unfortunately- these types of conspiracy theory claims are going to be more popular: the kids with little or no education trying to prove "physics was violated" like their bigger- and just as ignorant- counter-parts are doing: Jones, et al. It appeals to people grasping at straws and in some of these cases it takes a greater education to defeat the argument.

Although- I always fall back on logic.Uh...If you take a person and throuw them off a building the splatter when they hit the ground not because the ground is an orrosing force...well on the molecular level the electromagnetic force far outweighs gravity but that is NOT what the shyster means. He wouldn't know proper phydics if it bit him in the butt.

[gumboot]

example #1...

African woman holds water vase atop her head.

example #2...

Take said vase, lift it 8-12 feet up from her head, then drop it.

DO I have to say more...

TAM:)



Herein lies the single problem I have with the WTC collapse, and the only gap in my understanding.

I understand the above, which is an illustration of the difference between a dynamic load and a static load.

Let's modify your scenario a little, and make it a heavy solid bronze statue, sitting on a desk.

Just sitting there, obviously the force of gravity pushing the statue down matches the net force of the table resisting it.

Obviously if you lift the statue up and drop it, it will hit the table with more force than it has just sitting there. Much more. But it might crash into the desk and then stop, or it might hit the desk with enough force that the desk collapses.

My issue is, we know roughly how big the statue is and we know how high it fell from, and we know it made the desk collapse. Why can't we calculate the force involved in the impact collision?

We know NIST didn't present it, and we know CTers latch onto this like limpets onto a rock.

My question is, can we present it, even in simplified form? Wouldn't this be useful?

In the early days I was told NIST didn't present this calculation because it was very simple physics that the intact floors couldn't resist such an impact. I can accept that. But if it's simple, presenting a (simplified) calculation should be simple.

Alternatively, if it's actually highly complex (as some are now proposing here), shouldn't that be something NIST should have considered calculating? I would have thought it would be a useful thing to consider in building design and safety.

Or alternatively, is it a given in structural design that a total failure of 1 or 2 or 3 floors would always result in a global collapse?

Or finally another option, in the reality the initial impact event itself is so complex that NIST couldn't calculate it? (Even in simplistic form?).

Just to be clear, I am quite capable of accepting any of the above explanations, it's just right now this single part of the entire thing hasn't been explained to me. Hopefully someone can fill in the gap?

-Gumboot

[T.A.M.]

I hear ya...and agree. My understanding of mechanical physics is college 1st-2nd year level, but it is also over a decade since I had to use it.

If any of the mechanical engineers amongst us would care to show us, through simplified calculations, why the towers collapsed via the top portion coming atop the bottom, it would be most helpful.

TAM:)

[bje]

Herein lies the single problem I have with the WTC collapse, and the only gap in my understanding.

...

My issue is, we know roughly how big the statue is and we know how high it fell from, and we know it made the desk collapse. Why can't we calculate the force involved in the impact collision?

Isn't that what Frank Greening attempted to do?

[AZCat]

Herein lies the single problem I have with the WTC collapse, and the only gap in my understanding.

I understand the above, which is an illustration of the difference between a dynamic load and a static load.

Let's modify your scenario a little, and make it a heavy solid bronze statue, sitting on a desk.

Just sitting there, obviously the force of gravity pushing the statue down matches the net force of the table resisting it.

Obviously if you lift the statue up and drop it, it will hit the table with more force than it has just sitting there. Much more. But it might crash into the desk and then stop, or it might hit the desk with enough force that the desk collapses.

My issue is, we know roughly how big the statue is and we know how high it fell from, and we know it made the desk collapse. Why can't we calculate the force involved in the impact collision?

We know NIST didn't present it, and we know CTers latch onto this like limpets onto a rock.

My question is, can we present it, even in simplified form? Wouldn't this be useful?

In the early days I was told NIST didn't present this calculation because it was very simple physics that the intact floors couldn't resist such an impact. I can accept that. But if it's simple, presenting a (simplified) calculation should be simple.

Alternatively, if it's actually highly complex (as some are now proposing here), shouldn't that be something NIST should have considered calculating? I would have thought it would be a useful thing to consider in building design and safety.

Or alternatively, is it a given in structural design that a total failure of 1 or 2 or 3 floors would always result in a global collapse?

Or finally another option, in the reality the initial impact event itself is so complex that NIST couldn't calculate it? (Even in simplistic form?).

Just to be clear, I am quite capable of accepting any of the above explanations, it's just right now this single part of the entire thing hasn't been explained to me. Hopefully someone can fill in the gap?

-Gumboot

The problem is that impact dynamics is a particular kind of "complex". You may have heard of "chaotic systems" or "nonlinear systems" - systems where small changes in the initial conditions can cause wildly different results. Impact dynamics is like this. The collapse of the towers could have been modelled, although it would have taken quite some time (because of the numerical complexity) but it would not provide much of an answer about the probable behavior of the towers, because small differences in the initial assumptions of the NIST could cause drastically different collapse scenarios.

Sometimes when faced with this sort of problem, an analyst will do something called a "Monte Carlo method" (there are other techniques) whereas the initial conditions are tweaked randomly for each of a large set of simulation runs. This gives a distribution of the behavior of the system within a certain range of initial conditions, and can be more illuminating than a single run because it shows if the system behaves consistently or if it is particularly sensitive to changes in certain initial values. Unfortunately this means that the simulation must be run multiple times, which of course takes much longer than a single run. More importantly, even if the distribution shows that collapse is unlikely given those approximate initial conditions, we aren't trying to predict behavior - we are trying to analyze a single event, and probability has no real applicability in such an analysis.

[gumboot]

The problem is that impact dynamics is a particular kind of "complex". You may have heard of "chaotic systems" or "nonlinear systems" - systems where small changes in the initial conditions can cause wildly different results. Impact dynamics is like this. The collapse of the towers could have been modelled, although it would have taken quite some time (because of the numerical complexity) but it would not provide much of an answer about the probable behavior of the towers, because small differences in the initial assumptions of the NIST could cause drastically different collapse scenarios.

Sometimes when faced with this sort of problem, an analyst will do something called a "Monte Carlo method" (there are other techniques) whereas the initial conditions are tweaked randomly for each of a large set of simulation runs. This gives a distribution of the behavior of the system within a certain range of initial conditions, and can be more illuminating than a single run because it shows if the system behaves consistently or if it is particularly sensitive to changes in certain initial values. Unfortunately this means that the simulation must be run multiple times, which of course takes much longer than a single run. More importantly, even if the distribution shows that collapse is unlikely given those approximate initial conditions, we aren't trying to predict behavior - we are trying to analyze a single event, and probability has no real applicability in such an analysis.



I understand. I wasn't proposing the entire collapse - I imagine the variables in such a scenario would be literally billions, beyond the processing power of modern computers.

I'm simply talking the initial moment of impact, when the upper intact section of each tower came in contact with the first floor of the lower intact section of each tower.

Essentially, I suppose, what I'm referring to is the collapse of the first intact floor, rather than the collapse of the 92 (WTC1) or 76 (WTC2) floors below that.

-Gumboot

[AZCat]

I understand. I wasn't proposing the entire collapse - I imagine the variables in such a scenario would be literally billions, beyond the processing power of modern computers.

I'm simply talking the initial moment of impact, when the upper intact section of each tower came in contact with the first floor of the lower intact section of each tower.

Essentially, I suppose, what I'm referring to is the collapse of the first intact floor, rather than the collapse of the 92 (WTC1) or 76 (WTC2) floors below that.

-Gumboot

Modern computers are capable of handling quite impressive arrays (or rather matrices) of numbers, even in the billions. I'm not sure where the practical limits are - we'd have to find a compsci person to probably find that out.

The problem is this - if the assumption is that the upper intact section (UIS) essentially free-falls before striking the lower intact section (LIS) then the following are of concern:

1. What is the shape of the UIS after it breaks free from the supports? Has it deformed under loading?

2. What is the orientation of the UIS as it falls (probably dynamic, as the upper portion rotated)?

3. What is the shape of the LIS in our simplified model? Since we are trying to model free-fall for the UIS, what is left in the interstitial space between LIS and UIS?

We also have to look at how sensitive our model is to our answers to the three questions. Techniques such as Monte Carlo let you examine such sensitivity, so I don't think there's a way around it, but since this is a far less complex model (at least numerically) than the total collapse scenario it will therefore take much less time to run a block of simulations. It's still non-trivial, though, and will require a computer.

[Dr Adequate]

What is it with nutters and thermodynamics?

[gumboot]

Modern computers are capable of handling quite impressive arrays (or rather matrices) of numbers, even in the billions. I'm not sure where the practical limits are - we'd have to find a compsci person to probably find that out.

The problem is this - if the assumption is that the upper intact section (UIS) essentially free-falls before striking the lower intact section (LIS) then the following are of concern:

1. What is the shape of the UIS after it breaks free from the supports? Has it deformed under loading?

2. What is the orientation of the UIS as it falls (probably dynamic, as the upper portion rotated)?

3. What is the shape of the LIS in our simplified model? Since we are trying to model free-fall for the UIS, what is left in the interstitial space between LIS and UIS?

We also have to look at how sensitive our model is to our answers to the three questions. Techniques such as Monte Carlo let you examine such sensitivity, so I don't think there's a way around it, but since this is a far less complex model (at least numerically) than the total collapse scenario it will therefore take much less time to run a block of simulations. It's still non-trivial, though, and will require a computer.


Thanks for the info... I suppose in the scenario I was trying to work on (it's quite hilarious, kind of like a blind man trying to build an Ark) in response to those questions...

My simplified scenario is such that the aircraft impact zone essentially is just completely removed, with UIS and LIS completely intact. Given the UIS twisted, I dealign the columns so that the columns of the UIS do not line up exactly with the columns of the LIS (in other words they strike the floor truss instead) however, assuming that the UIS is level at impact thus the force is spread evenly across the entire footprint of all 287 columns.

Hrm, see now I'm thinking maybe it's just that my simplified scenario is too simplified - as in it's so simplified it's not useful as even a starting point.

My head hurts. :(

(And thank you AZCat for your patience)

-Gumboot

[jsiv]

"Each floor held up all the floors above it?"

[westprog]

I understand. I wasn't proposing the entire collapse - I imagine the variables in such a scenario would be literally billions, beyond the processing power of modern computers.

I'm simply talking the initial moment of impact, when the upper intact section of each tower came in contact with the first floor of the lower intact section of each tower.

Essentially, I suppose, what I'm referring to is the collapse of the first intact floor, rather than the collapse of the 92 (WTC1) or 76 (WTC2) floors below that.

-Gumboot

The energy calculation is fairly easy. The force calculation isn't. The energy can be calculated using the mgh formula - m is mass, g acceleration due to gravity, and h the height difference. Calculating the mass of the falling portion of the building involves a bit of approximation, but it's not too difficult to get a ballpark figure. (The fact that the bottom part of the building weighed more than the top maens that it's not just a matter of allocating weight to floors).

Once the energy calculation is made, most of the CT objections just vanish. They simply don't understand just how powerful gravity is.

That's not to say that a force or momentum based analysis is pointless, but it's more difficult to do.

[AZCat]

Thanks for the info... I suppose in the scenario I was trying to work on (it's quite hilarious, kind of like a blind man trying to build an Ark) in response to those questions...

My simplified scenario is such that the aircraft impact zone essentially is just completely removed, with UIS and LIS completely intact. Given the UIS twisted, I dealign the columns so that the columns of the UIS do not line up exactly with the columns of the LIS (in other words they strike the floor truss instead) however, assuming that the UIS is level at impact thus the force is spread evenly across the entire footprint of all 287 columns.

Hrm, see now I'm thinking maybe it's just that my simplified scenario is too simplified - as in it's so simplified it's not useful as even a starting point.

My head hurts. :(

(And thank you AZCat for your patience)

-Gumboot

No sweat, Gumboot - this is my equivalent of a "busman's holiday". This isn't my area (I do building thermal stuff) so I can't tell you much more about how we could analyze this, but somebody here probably has the necessary knowledge. It might also be a good topic for someon's Phd. thesis (hint, hint - to any potential prof's).

[Quad4_72]

I think the guy in the video just really enjoyed hearing himself say "Force=Net zero". Must make him feel like he understands physics. Not only are there so many other factors that he leaves unaccounted for, he just simply has no grasp of the very basic concepts of physics. I have a feeling that he is the loner at his school and he has became wrapped around conspiracy theories because the people that agree with him make him feel accepted. Its sad really.

[MarkyX]

I think the guy in the video just really enjoyed hearing himself say "Force=Net zero". Must make him feel like he understands physics. Not only are there so many other factors that he leaves unaccounted for, he just simply has no grasp of the very basic concepts of physics. I have a feeling that he is the loner at his school and he has became wrapped around conspiracy theories because the people that agree with him make him feel accepted. Its sad really.

You can say that about any internet group such as Furries or Yaoi fanfiction writers. Don't google those two examples.

The owner of the humor site SomethingAwful.com, Rich "Lowtax" Kyanka, was invited into a university talking about online communities and just how messed up they are. A really interesting look at the whole affair.

EDIT: Found it.

http://www.somethingawful.com/d/comedy-goldmine/lowtax-speaks-at.php

[stilicho]

This is odd that people think the towers ought to have been still standing. Even the firefighters apparently believed and trusted that the buildings would survive. Otherwise they certainly wouldn't have gone into them. (And, forgotten by the truthers, after seeing what happened to the two towers, would any human being--let alone an emergency worker--have dared entering WTC7 after just seeing the 'impossible' happen to the twin towers?)

But, a total layman on things like structural engineering and physics, I remember watching CNN on SEP 11 and thinking to myself that this was a fascinating yet doomed scenario. Just having known a small bit about those kind of buildings. I worked in one similar to those three buildings, just 34 storeys, but one of the orientation talks was about two potential dangers--an explosion in 'plant' and a plane collision. They never talked about possible collapse but they emphasised evacuation procedures in either case. (The municipal airport was only a couple of kilometres from the building so the risk was definitely there. A Cessna crashed into a hospital closer to the airport once when the pilot lost consciousness on his approach.)

Being a few hours behind New York time, I was able to watch most of the beginning of the scenario, and by the time I got to work, I was told they had collapsed. But it sure didn't surprise me. Why on earth's name do lay people think they ought to have withstood the crashes and fires? I do hope that these 'professors' get their credentials re-examined. Just as I do 'Harvard psychiatrists' who believe in alien abductions.

[gumboot]

This is odd that people think the towers ought to have been still standing. Even the firefighters apparently believed and trusted that the buildings would survive. Otherwise they certainly wouldn't have gone into them.



To be fair the FDNY realised the structure's integrity was in serious doubt pretty quickly, and ordered an immediate full evacuation of all FDNY personnel.

Some heard it and decided to continue trying to reach the fires anyway, others never heard it because of problems with the radios. Only a few actually responded and left the buildings.

-Gumboot

[defaultdotxbe]

To be fair the FDNY realised the structure's integrity was in serious doubt pretty quickly, and ordered an immediate full evacuation of all FDNY personnel.

Some heard it and decided to continue trying to reach the fires anyway, others never heard it because of problems with the radios. Only a few actually responded and left the buildings.

-Gumboot
or they chose to go into the towers because there were still people inside who needed to be evacuated

[gumboot]

or they chose to go into the towers because there were still people inside who needed to be evacuated


Yeah that's what I meant by the first one.

The order came after they were in the towers... so no one went up the stairs (at least in WTC1) after it was issued. But a lot of guys heard it and kept going up anyway.

-Gumboot

[T.A.M.]

It makes me cringe every time I hear a truther utter...

"For every action there is an equal, and opposite, reaction..." as if this answers any and every problem regarding the collapses...twirps.

TAM:)

[Myriad]

Gumboot, it is possible to answer your question in a simple way, using only F=ma, if you make lots of simplifying assumptions. Let's start with your already simplified case of simply dropping the upper 1/5 of the tower through 1 storey of open air onto the lower tower.

In order for the lower portion of the tower to arrest the collapse, the upper portion of the tower, already in motion, now has to stop moving. (Even if it were possible for it to "topple to the side" at that point, its vertical motion still has to stop or else it will keep smashing downward through the lower tower instead.)

To go from falling to at-rest, the moving mass must accelerate upward. The structure it falls onto must provide sufficient force for a sufficient amount of time to accelerate the moving mass to zero downward velocity. A lot of force over a short time will do, or a lesser force over a longer time.

How much time does the lower structure have to decelerate the upper mass? Actually that's not quite the right question yet. Let's look at the moment the masses come in contact. The lower mass starts resisting, and the upper mass starts decelerating. But it can't decelerate instantly, that would take infinite force. So the upper mass is still moving after it comes in contact with the lower. The greater the resistive force, the faster the moving mass will accelerate (slow down), and the less distance it will therefore move before it comes to rest. If the resistive force is less, the moving mass will accelerate to zero over a greater distance. (If the resistive force is less than or equal to the gravitational force acting on the falling mass (that is to say, its weight), the moving mass won't slow down at all, it will keep going and possibly accelerating downward. But we expect the resistive force to be greater than the falling mass's weight, because the lower tower was designed to support that weight.)

But as long as the upper mass is still moving, the lower structure that's providing the force to slow it down is also being deformed by that movement. That deformation is going to weaken the lower structure, reducing the force with which it acts against the moving upper mass. So we can transform the question of how much time does it take for the lower structure to bring the upper portion to rest, into over what distance (amount of deformation) can the resistive force continue to act upon the upper mass? This is where it gets complicated, because different kinds of deformation (buckling, fracturing, etc.) will affect the resistance in different ways over different amounts of time and distances. But we can look at ultra-simplified models of this.

Let's say, for instance, that when the upper mass smashes into the next floor down, that next floor will fail completely, cease to offer any resistance, once it is deformed (pushed downward) by half a meter. And let's also say that until then, it resists with its full designed strength. So, the floor must resist with sufficient force to bring the upper mass to a stop in half a meter or less, or else the collapse will continue to the next floor.

In your floor-removed scenario, the upper mass accelerates freely at g for 3 meters. It must decelerate at 6g to come to rest again in .5 meters. (For any given change in velocity, the acceleration needed to cause that change in velocity over a given distance is inversely proportional to that distance.) Therefore the floor it lands on must provide a force of 6 times the (static) weight of the upper mass -- actually 7 times, because it also must resist the gravitational force that's still acting on the upper mass as it falls.

The structures, of course, were not built with 7x redundancy in the amount of upward force they could exert (that is, weight they could bear). The best estimates of their excess capacity seem to be about 1.6x. So, the floor cannot bring the upper mass to rest within .5 meters of deformation. Not even close.

In fact, over the .5 meter distance, in this scenario, the falling mass only is accelerated upward (that is, slowed down) by .6g over a distance of half a meter. Of the velocity it's attained by falling 3 meters at g, it loses only 1/10th of that velocity as a result of the floor's resistance -- after which it has another 3 meters to accelerate at g before hitting the next floor.

I find this a useful mental model to look at the collapses, because it's easy to examine what happens when you change some of the parameters. For instance, you can ask questions like "how far would each floor of the lower structure have to be able to deform, without losing any strength, in order for the falling mass to get progressively slower and eventually stop -- assuming that none of the mass in the lower tower gets added to the falling mass along the way? For a floor-floor distance of 3.5 meters and a "deformation at full strength" distance d, the increase in velocity is proportional to the square root of (g *(3.5 - d)) and the decrease in velocity is proportional to the square root of (.6 * g * d). The decrease becomes greater when the deformation distance is greater than ~2.2 meters.

Of the two biggest assumptions in this model, one works unrealistically in favor of collapse and the other against it. The one that's biased in favor of collapse is the assumption that the upper mass is able to accelerate at g for nearly a whole storey before meeting any resistance. The one that's biased against collapse is that the lower tower is able to resist the force of the falling mass with its full designed load strength, when the upper mass is actually displaced horizontally and tilting, concentrating forces instead of evenly distributing them.

While far short of adequate for any real engineering analysis, this kind of calculation does help me understand why structural engineers are so sure that "collapse is inevitable" once entire upper storeys of a tower start moving. If the structure were strong enough to arrest (literally, bring to rest) the collapsing floors, it would have been strong enough for the floors to not start moving in the first place, even as damaged as they were. (Which probably would have been way too over-buit for any practical economic use.)

That, of course, is why NIST focused on collapse initiation as the key engineering issue here.

Respectfully,
Myriad

[qarnos]

Gumboot, it is possible to answer your question in a simple way, using only F=ma, if you make lots of simplifying assumptions. Let's start with your already simplified case of simply dropping the upper 1/5 of the tower through 1 storey of open air onto the lower tower.

In order for the lower portion of the tower to arrest the collapse, the upper portion of the tower, already in motion, now has to stop moving. (Even if it were possible for it to "topple to the side" at that point, its vertical motion still has to stop or else it will keep smashing downward through the lower tower instead.)

To go from falling to at-rest, the moving mass must accelerate upward. The structure it falls onto must provide sufficient force for a sufficient amount of time to accelerate the moving mass to zero downward velocity. A lot of force over a short time will do, or a lesser force over a longer time.

How much time does the lower structure have to decelerate the upper mass? Actually that's not quite the right question yet. Let's look at the moment the masses come in contact. The lower mass starts resisting, and the upper mass starts decelerating. But it can't decelerate instantly, that would take infinite force. So the upper mass is still moving after it comes in contact with the lower. The greater the resistive force, the faster the moving mass will accelerate (slow down), and the less distance it will therefore move before it comes to rest. If the resistive force is less, the moving mass will accelerate to zero over a greater distance. (If the resistive force is less than or equal to the gravitational force acting on the falling mass (that is to say, its weight), the moving mass won't slow down at all, it will keep going and possibly accelerating downward. But we expect the resistive force to be greater than the falling mass's weight, because the lower tower was designed to support that weight.)

But as long as the upper mass is still moving, the lower structure that's providing the force to slow it down is also being deformed by that movement. That deformation is going to weaken the lower structure, reducing the force with which it acts against the moving upper mass. So we can transform the question of how much time does it take for the lower structure to bring the upper portion to rest, into over what distance (amount of deformation) can the resistive force continue to act upon the upper mass? This is where it gets complicated, because different kinds of deformation (buckling, fracturing, etc.) will affect the resistance in different ways over different amounts of time and distances. But we can look at ultra-simplified models of this.

Let's say, for instance, that when the upper mass smashes into the next floor down, that next floor will fail completely, cease to offer any resistance, once it is deformed (pushed downward) by half a meter. And let's also say that until then, it resists with its full designed strength. So, the floor must resist with sufficient force to bring the upper mass to a stop in half a meter or less, or else the collapse will continue to the next floor.

In your floor-removed scenario, the upper mass accelerates freely at g for 3 meters. It must decelerate at 6g to come to rest again in .5 meters. (For any given change in velocity, the acceleration needed to cause that change in velocity over a given distance is inversely proportional to that distance.) Therefore the floor it lands on must provide a force of 6 times the (static) weight of the upper mass -- actually 7 times, because it also must resist the gravitational force that's still acting on the upper mass as it falls.

The structures, of course, were not built with 7x redundancy in the amount of upward force they could exert (that is, weight they could bear). The best estimates of their excess capacity seem to be about 1.6x. So, the floor cannot bring the upper mass to rest within .5 meters of deformation. Not even close.

In fact, over the .5 meter distance, in this scenario, the falling mass only is accelerated upward (that is, slowed down) by .6g over a distance of half a meter. Of the velocity it's attained by falling 3 meters at g, it loses only 1/10th of that velocity as a result of the floor's resistance -- after which it has another 3 meters to accelerate at g before hitting the next floor.

I find this a useful mental model to look at the collapses, because it's easy to examine what happens when you change some of the parameters. For instance, you can ask questions like "how far would each floor of the lower structure have to be able to deform, without losing any strength, in order for the falling mass to get progressively slower and eventually stop -- assuming that none of the mass in the lower tower gets added to the falling mass along the way? For a floor-floor distance of 3.5 meters and a "deformation at full strength" distance d, the increase in velocity is proportional to the square root of (g *(3.5 - d)) and the decrease in velocity is proportional to the square root of (.6 * g * d). The decrease becomes greater when the deformation distance is greater than ~2.2 meters.

Of the two biggest assumptions in this model, one works unrealistically in favor of collapse and the other against it. The one that's biased in favor of collapse is the assumption that the upper mass is able to accelerate at g for nearly a whole storey before meeting any resistance. The one that's biased against collapse is that the lower tower is able to resist the force of the falling mass with its full designed load strength, when the upper mass is actually displaced horizontally and tilting, concentrating forces instead of evenly distributing them.

While far short of adequate for any real engineering analysis, this kind of calculation does help me understand why structural engineers are so sure that "collapse is inevitable" once entire upper storeys of a tower start moving. If the structure were strong enough to arrest (literally, bring to rest) the collapsing floors, it would have been strong enough for the floors to not start moving in the first place, even as damaged as they were. (Which probably would have been way too over-buit for any practical economic use.)

That, of course, is why NIST focused on collapse initiation as the key engineering issue here.

Respectfully,
Myriad

But Fnet = 0!
It's a constant! It doesn't change! :D

Nice work, BTW! It may be oversimplified, but it demonstrates the tremendous forces involved.

[gumboot]

Gumboot, it is possible to answer your question in a simple way, using only F=ma, if you make lots of simplifying assumptions.

...

While far short of adequate for any real engineering analysis, this kind of calculation does help me understand why structural engineers are so sure that "collapse is inevitable" once entire upper storeys of a tower start moving. If the structure were strong enough to arrest (literally, bring to rest) the collapsing floors, it would have been strong enough for the floors to not start moving in the first place, even as damaged as they were. (Which probably would have been way too over-buit for any practical economic use.)

That, of course, is why NIST focused on collapse initiation as the key engineering issue here.

Respectfully,
Myriad



Thank you, that's certainly enough for me to fill in that "hole" in my understanding. And I can see entirely why it would be difficult to do a serious calculation.

One thing that jumped out at me - based on the single floor fall, the force involved is already significant. If you consider that in reality a number of floors failed simultaneously, the initial impact force becomes even greater (unless I'm mistaken, in WTC1 you're talking 36g's and for WTC2 you're talking 52g's).

In regards to the particular assumption that the initial collapsing floors offer no resistance, it is an over simplification, but I don't think it's an enormous one. Bear in mind, the floors in the aircraft impact zone were severely damaged and sagging prior to collapse initiation. The only thing really keeping them up was the exterior core columns (indeed if the 9-1-1 calls are anything to go by some of these floors were already starting to collapse before the exterior columns buckled). Once the bowing inwards caused the columns to fail, the only thing left between the upper mass and the intact floor below the aircraft impact zone was the core columns. As the building twisted as it fell, it's likely none of the core columns lined up, thus there was literally nothing resisting the upper mass for a distance of 18m (WTC1) and 26m (WTC2).

Actually, scratch that, that's not true. The first intact floor truss in the UPPER mass would have met resistance from the core columns after a fall of one floor (assuming it was still intact).

-Gumboot

[Miragememories]

This is what happens when an incomplete education prevents someone from being able to scientifically understand something. I'm no physics expert, but it's painfully easy to see what mistakes he's making.

I'm curious Totovader what exactly are you an expert at?

Hopefully mine and other future responses can prevent you from suffering pain in whatever field of endeavour it is that you think you have some expertise in?

MM

[beachnut]

I'm curious Totovader what exactly are you an expert at?

Hopefully mine and other future responses can prevent you from suffering pain in whatever field of endeavour it is that you think you have some expertise in?

MM
It only takes a rational mind to discover the physics lesson from that truther is below the 1st grade level. I have seen ants capable of better understanding of physics in action then the rant of the video physics dolt.

Do you agree? What did the truther physics guy get right? What did he get wrong? Please explain why most have a problem with his WTC model and if you agree or disagree that most engineers would give him a poor grade for being wrong?

[Totovader]

I'm curious Totovader what exactly are you an expert at?

Hopefully mine and other future responses can prevent you from suffering pain in whatever field of endeavour it is that you think you have some expertise in?

MM

Your curiosity is none of my concern.

[AZCat]

Wow. I just watched about 2/3 of the first part and couldn't take anymore. I'm not going to fault anyone for not knowing this stuff - it's not like everyone needs to understand it - but if you don't have a very good grasp of an area why in the world would you make a YouTube video of yourself trying to explain something in that area, especially when there are thousands of other people out there, all more knowledgeable than you, who disagree with your conclusions?

[Horatius]

....but if you don't have a very good grasp of an area why in the world would you ...



That's just it. These guys think they do have a good grasp of physics. They insist it's everybody else who has it wrong.

I have no idea how to fix this.

[Gravy]

I understand. I wasn't proposing the entire collapse - I imagine the variables in such a scenario would be literally billions, beyond the processing power of modern computers.

I'm simply talking the initial moment of impact, when the upper intact section of each tower came in contact with the first floor of the lower intact section of each tower.

Essentially, I suppose, what I'm referring to is the collapse of the first intact floor, rather than the collapse of the 92 (WTC1) or 76 (WTC2) floors below that.

-Gumboot

Bazant & Zhou (2002) (http://www.911-strike.com/BazantZhou.htm) and Bazant & Verdure (2006) (http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/ProgressiveCollapseWTC-6-23-2006.pdf) examine the energy requirements for collapse progression. A summary from the 2006 paper:

The kinetic energy of the top part of the tower impacting the floor below was found to be about 8.4x larger than the plastic energy absorption capability of the underlying story, and considerably higher than that if fracturing were taken into account (Bažant and Zhou 2002a). This fact, along with the fact that during the progressive collapse of underlying stories the loss of gravitational potential per story is much greater than the energy dissipated per story, was sufficient for Bažant and Zhou (2002a) to conclude, purely on energy grounds, that the tower was doomed once the top part of the tower dropped through the height of one story (or even 0.5 m). It was also observed that this conclusion made any calculations of the dynamics of progressive collapse after the first single-story drop of upper part superfluous. The relative smallness of energy absorption capability compared to the kinetic energy also sufficed to explain, without any further calculations, why the collapse duration could not have been much longer (say, twice as long or more) than the duration of a free fall from the tower top.

Therefore, no further analysis has been necessary to prove that the WTC towers had to fall the way they did, due to gravity alone. However, a theory describing the progressive collapse dynamics beyond the initial trigger, with the WTC as a paradigm, could nevertheless be very useful for other purposes, especially for learning from demolitions. It could also help to clear up misunderstanding (and thus to dispel the myth of planted explosives).(His progressive collapse theory follows that intro.)

Zdenek Bazant responds to G.P. Cherepanov's critique (http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/Progre-RebutCherepanovCritiqueOfBazZhouWTC-06.pdf)

Greening's paper on the Tower Collapses (http://www.911myths.com/WTCREPORT.pdf) presents calculations that are mostly easy for a mathematical dummy like me to follow. (I do think he overestimates the mass of the upper portions of the buildings.)

On page 8 Greening calculates the kinetic energy of the upper portion of WTC 1 to be 23.4 x 10^8 Joules, with 3.3% of that lost to heat, and WTC 2 to be 48.4 x 10^8 Joules, with 6.7% lost to heat.

[AZCat]

That's just it. These guys think they do have a good grasp of physics. They insist it's everybody else who has it wrong.

I have no idea how to fix this.

I don't know either. After all, "you can lead a horse to water but you can't make him drink."

When confronted with evidence that their understanding is flawed, they just get more shrill and defensive rather than examining the arguments. I have no idea how they function in real life, although a number of the more well-known truthers certainly have had difficulty. Steven Jones lost his job, as did Kevin Ryan and Judy Woods.

[Cl1mh4224rd]

I notice that someone got a shot off- they asked him if he had shown this to his professor, he said that his high school teacher agreed with him...

The obvious counter-question to this would be, "What subject did this high school teacher teach?"

[Totovader]

The obvious counter-question to this would be, "What subject did this high school teacher teach?"

:)

Spoken like a true skeptic.

[Furcifer]

most high schools can't get qualified people to teach the higher level math and physics subjects. it simply falls on the most qualified. physics more so than math. my graduating class in physics was 8, i think there were 30 in math. i know of 2 math majors that went on to teach, none in physics.

[~enigma~]

The obvious counter-question to this would be, "What subject did this high school teacher teach?"
English :)

[Miragememories]

It only takes a rational mind to discover the physics lesson from that truther is below the 1st grade level. I have seen ants capable of better understanding of physics in action then the rant of the video physics dolt.

Do you agree? What did the truther physics guy get right? What did he get wrong? Please explain why most have a problem with his WTC model and if you agree or disagree that most engineers would give him a poor grade for being wrong?

I'll return to your sandbox tomorrow beachnut.

MM

[Miragememories]

Bazant & Zhou (2002) (http://www.911-strike.com/BazantZhou.htm) and Bazant & Verdure (2006) (http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/ProgressiveCollapseWTC-6-23-2006.pdf) examine the energy requirements for collapse progression. A summary from the 2006 paper:

(His progressive collapse theory follows that intro.)

Zdenek Bazant responds to G.P. Cherepanov's critique (http://www.civil.northwestern.edu/people/bazant/PDFs/Papers/Progre-RebutCherepanovCritiqueOfBazZhouWTC-06.pdf)

Greening's paper on the Tower Collapses (http://www.911myths.com/WTCREPORT.pdf) presents calculations that are mostly easy for a mathematical dummy like me to follow. (I do think he overestimates the mass of the upper portions of the buildings.)

On page 8 Greening calculates the kinetic energy of the upper portion of WTC 1 to be 23.4 x 10^8 Joules, with 3.3% of that lost to heat, and WTC 2 to be 48.4 x 10^8 Joules, with 6.7% lost to heat.

Too bad this post reveals an inability to explain the content. Cut and paste is easy, but explanations are obviously incredibly challenging when engineering is not the posters area of expertise.

MM


Edited to remove insult under the current more stringent interpretation of the membership agreement in this forum. Attack the argument, not the person.

[T.A.M.]

now MM, Mark is no dummy, even in math. He was obviously making a joke. You must have been as well, because I know you know the new moderating rules well, and we wouldn't want to have to report you for insinuating someone here was a "dummy". That is insulting.

TAM;)

[gumboot]

most high schools can't get qualified people to teach the higher level math and physics subjects. it simply falls on the most qualified. physics more so than math. my graduating class in physics was 8, i think there were 30 in math. i know of 2 math majors that went on to teach, none in physics.



Depends on the country.

This guy sounds like he's a South African from Australia.

-Gumboot

[Horatius]

The obvious counter-question to this would be, "What subject did this high school teacher teach?"

most high schools can't get qualified people to teach the higher level math and physics subjects. it simply falls on the most qualified. physics more so than math. my graduating class in physics was 8, i think there were 30 in math. i know of 2 math majors that went on to teach, none in physics.



This is very true, at least in my experience. I was lucky to have a highshool physics teacher who actually understood physics. Most of the people I've met later in life didn't. And he was the only one qualified to teach physics in the whole school. He was stuck doing it for years. I looked into teaching for a while after university, and they really wanted me, because there was no one to take over physics after he retired. Stupid union rules said they couldn't hire me though, as I didn't have a teacher's certificate, and my efforts to get one were thwarted :(



now MM, Mark is no dummy, even in math. He was obviously making a joke.




I'm beginning to notice a lot of twoofer types are seriously humour-impaired. They don't seem to recognize or understand jokes, and when they try to be funny, they fail utterly and completely.

Someone should do a paper on that :)

[SYLVESTER1592]

He's blocked everyone from posting who doesn't agree with him. I've had most of my comments removed even after I reposted them- and then he blocked me as well. All I did was ask for his calculations.

I notice that someone got a shot off- they asked him if he had shown this to his professor, he said that his high school teacher agreed with him...

...

I find it hard to believe that the kid explained it to his high school teacher like he did on YouTube- but even if he had, this just emphasizes my point: an incomplete education is a very dangerous thing. By shutting out any disagreement- by not even questioning your conclusions- and by looking for confirming evidence, even if it means bastardizing science itself- we arrive at the core of conspiracy theories.

Unfortunately- these types of conspiracy theory claims are going to be more popular: the kids with little or no education trying to prove "physics was violated" like their bigger- and just as ignorant- counter-parts are doing: Jones, et al. It appeals to people grasping at straws and in some of these cases it takes a greater education to defeat the argument.

Although- I always fall back on logic.

Hi guys, I'm new here and was referred to this forum. I'm already converted, I don't understand everything and it takes me more effort and time to work everything out, since I'm not an engineer by trade, but I have improved my understanding of the physics behind the WTC collapse in discussions with a forum member and study of published papers on the subject
:blush:.

I hope I can contribute to this forum and I am at this point still looking at all the posts. I was referred to this post on JREF by a debunker after having been banned from the video site like totovader. I understand that a reply video has offered to allow an objective, open and honest discussion. I hope this helps.
:)

[gumboot]

Hi guys, I'm new here and was referred to this forum. I'm already converted, I don't understand everything and it takes me more effort and time to work everything out, since I'm not an engineer by trade, but I have improved my understanding of the physics behind the WTC collapse in discussions with a forum member and study of published papers on the subject
:blush:.

I hope I can contribute to this forum and I am at this point still looking at all the posts. I was referred to this post on JREF by a debunker after having been banned from the video site like totovader. I understand that a reply video has offered to allow an objective, open and honest discussion. I hope this helps.
:)



Hi there,

Welcome to the forums. :)

-Gumboot

[Slayhamlet]

Hi guys, I'm new here and was referred to this forum. I'm already converted, I don't understand everything and it takes me more effort and time to work everything out, since I'm not an engineer by trade, but I have improved my understanding of the physics behind the WTC collapse in discussions with a forum member and study of published papers on the subject
:blush:.

I hope I can contribute to this forum and I am at this point still looking at all the posts. I was referred to this post on JREF by a debunker after having been banned from the video site like totovader. I understand that a reply video has offered to allow an objective, open and honest discussion. I hope this helps.
:)

Argh, don't use that word! It makes me cringe. We're not dealing with religious affiliations here!
I suggest "disillusioned", instead. It's much more accurate, and it sounds better. ;)

Oh, and welcome! :)

[SYLVESTER1592]

Argh, don't use that word! It makes me cringe. We're not dealing with religious affiliations here!
I suggest "disillusioned", instead. It's much more accurate, and it sounds better. ;)

Oh, and welcome! :)


I'm sorry.
:o
Sometimes points of view are so rigorous and immune to reason that they seem more based on faith. I completely agree that faith has no place in a scientific forum. You're right, disillusioned or corrected sounds better.
:)

[westprog]

Gumboot, it is possible to answer your question in a simple way, using only F=ma, if you make lots of simplifying assumptions. Let's start with your already simplified case of simply dropping the upper 1/5 of the tower through 1 storey of open air onto the lower tower.

In order for the lower portion of the tower to arrest the collapse, the upper portion of the tower, already in motion, now has to stop moving. (Even if it were possible for it to "topple to the side" at that point, its vertical motion still has to stop or else it will keep smashing downward through the lower tower instead.)

To go from falling to at-rest, the moving mass must accelerate upward. The structure it falls onto must provide sufficient force for a sufficient amount of time to accelerate the moving mass to zero downward velocity. A lot of force over a short time will do, or a lesser force over a longer time.

How much time does the lower structure have to decelerate the upper mass? Actually that's not quite the right question yet. Let's look at the moment the masses come in contact. The lower mass starts resisting, and the upper mass starts decelerating. But it can't decelerate instantly, that would take infinite force. So the upper mass is still moving after it comes in contact with the lower. The greater the resistive force, the faster the moving mass will accelerate (slow down), and the less distance it will therefore move before it comes to rest. If the resistive force is less, the moving mass will accelerate to zero over a greater distance. (If the resistive force is less than or equal to the gravitational force acting on the falling mass (that is to say, its weight), the moving mass won't slow down at all, it will keep going and possibly accelerating downward. But we expect the resistive force to be greater than the falling mass's weight, because the lower tower was designed to support that weight.)

But as long as the upper mass is still moving, the lower structure that's providing the force to slow it down is also being deformed by that movement. That deformation is going to weaken the lower structure, reducing the force with which it acts against the moving upper mass. So we can transform the question of how much time does it take for the lower structure to bring the upper portion to rest, into over what distance (amount of deformation) can the resistive force continue to act upon the upper mass? This is where it gets complicated, because different kinds of deformation (buckling, fracturing, etc.) will affect the resistance in different ways over different amounts of time and distances. But we can look at ultra-simplified models of this.
...


Minor point - it's possible for the decelleration to involve deformation in the falling mass as well. There's a famous picture of a jet fighter hitting a concrete wall. It gets decellerated, and the structure remains essentially intact.

In the case of the WTC, the two structures (top bit and bottom bit) are broadly similar, so one would expect both to be deformed by the decelleration in similar ways. However, it's a very complex issue, and I'm just trying to clarify. Though I may be unwittingly obfuscating.

[Totovader]

Hi guys, I'm new here and was referred to this forum. I'm already converted, I don't understand everything and it takes me more effort and time to work everything out, since I'm not an engineer by trade, but I have improved my understanding of the physics behind the WTC collapse in discussions with a forum member and study of published papers on the subject
:blush:.

I hope I can contribute to this forum and I am at this point still looking at all the posts. I was referred to this post on JREF by a debunker after having been banned from the video site like totovader. I understand that a reply video has offered to allow an objective, open and honest discussion. I hope this helps.
:)

Welcome, Sylvester1592!

[Zep]

The whole thing in the videos seem to involve a lot of irrational nonsense, hand-waving and shouting. If he was doing this on a soapbox in a park, people would just laugh and walk on by. Why do we do any different on YouTube?

[Totovader]

The whole thing in the videos seem to involve a lot of irrational nonsense, hand-waving and shouting. If he was doing this on a soapbox in a park, people would just laugh and walk on by. Why do we do any different on YouTube?

Because people in a park really don't give a crap- the majority of them don't believe that 9-11 was an inside job.

On YouTube, they're looking for it- and people like this give them the "scientific leverage" they know they need so badly.

Problem is- science is not at all in their favor. But it still takes a lot to point that out to them. When they see someone using big words and a pen and a drawing pad, they assume he's right because he's confirming their predetermined conclusion.

[Zep]

Is there a YouTube version of the WTC collapse that uses simple animation and simple physics explanations? Maybe something like that could go a LONG way to dispelling these raging nutters.

I'm sure there are some excellent JREFers who could construct such footage!

[tsig]

I hear ya...and agree. My understanding of mechanical physics is college 1st-2nd year level, but it is also over a decade since I had to use it.

If any of the mechanical engineers amongst us would care to show us, through simplified calculations, why the towers collapsed via the top portion coming atop the bottom, it would be most helpful.

TAM:)

Just how many times do you want it.

Or is it that you do not wish to know?

[MRC_Hans]

"The ground pushes up", wow that's just stupid. :jaw-droppUhh, not really. It is perhaps an unfortunate wording, but the ground provides the equal and opposite force that keeps a building from sinking in. If you placed it on water, it would sink in until the "push" from the water pressure on the bottom was equal to it's weight (ignoring that buildings are not watertight, etc.). So, on any building, the ground provides am upward "push" equal to the weight of the building. In fact, it also does the same for you.

Hans

[MRC_Hans]

What is it with nutters and thermodynamics?Well, lots of people don't understand thermodynamics. Nutters try to make conclusions from what they don't understand.

Hans

[gumboot]

Uhh, not really. It is perhaps an unfortunate wording, but the ground provides the equal and opposite force that keeps a building from sinking in. If you placed it on water, it would sink in until the "push" from the water pressure on the bottom was equal to it's weight (ignoring that buildings are not watertight, etc.). So, on any building, the ground provides am upward "push" equal to the weight of the building. In fact, it also does the same for you.

Hans



He's talking about "normal force", and although "the ground pushes up" is how it's explained to high school students, that's not really what it is. It's essentially the force delivered by a surface that prevents an object resting on that surface from penetrating through it.

Thus in the theoretical case of the upper section of the WTC falling on the lower section and stopping, it's the normal force of the upper surface of the lower section which is "pushing up" against the upper section to produce a net force of zero. Not the ground.

(Of course when the shock wave travels down through the steel to the ground, there's then another normal force from the ground surface acting on the bottom surface of the lower intact section to produce another net force of zero.)

-Gumboot

[tsig]

I think the guy in the video just really enjoyed hearing himself say "Force=Net zero". Must make him feel like he understands physics. Not only are there so many other factors that he leaves unaccounted for, he just simply has no grasp of the very basic concepts of physics. I have a feeling that he is the loner at his school and he has became wrapped around conspiracy theories because the people that agree with him make him feel accepted. Its sad really.


Someone failed physics

In all of your classes someone failed

[MRC_Hans]

He's talking about "normal force", and although "the ground pushes up" is how it's explained to high school students, that's not really what it is. It's essentially the force delivered by a surface that prevents an object resting on that surface from penetrating through it.

Oh, I'm not definding the chap in the video (does anybody know who he is?), I'm just pointing out that, in all fairness, saying that the ground pushes up, while a rather naive way to word it, is not incorrect.


Thus in the theoretical case of the upper section of the WTC falling on the lower section and stopping, it's the normal force of the upper surface of the lower section which is "pushing up" against the upper section to produce a net force of zero. Not the ground.


Oh, eventually, the force would be transferred to the ground. However, this whole line of argueing is indeed silly: IF the lower portion of the building had been strong enough to stop the top part, then the buildings would not have collapsed. And what exactly does that prove? It proves that the lower part of the building was not that strong. No more, no less.


(Of course when the shock wave travels down through the steel to the ground, there's then another normal force from the ground surface acting on the bottom surface of the lower intact section to produce another net force of zero.)


Right.

Hans

[gumboot]

Oh, eventually, the force would be transferred to the ground. However, this whole line of argueing is indeed silly: IF the lower portion of the building had been strong enough to stop the top part, then the buildings would not have collapsed. And what exactly does that prove? It proves that the lower part of the building was not that strong. No more, no less.



He seems to think that some how a surface's normal force is capable of changing directly proportional to the force acting on it... :faint:

-Gumboot

[R.Mackey]

Too bad this post reveals an inability to explain the content. Cut and paste is easy, but explanations are obviously incredibly challenging when engineering is not the posters area of expertise.

I think the "mathematical dummy" part was easy to understand and I have to agree with that conclusion.

(ahem)

It was cut and pasted from Volume 1 JOURNAL OF HOW THINGS WORK The Physics of Karate Strikes
http://forums.randi.org/showpost.php?p=2540495&postcount=476
http://72.14.253.104/search?q=cache:NC8XquAO4T4J:howthingswork.virginia .edu/journal/Article1.1.pdf+where+e+is+the+coefficient+of+resti tution,+which+measures+how+elastic+the+collision+i s.+It+is+a+function+of+the+hardness+or+softness+of +the+colliding+objects&hl=en&ct=clnk&cd=1&gl=us
And this somehow invalidates the argument?

It only proves content means nothing and that this is all just a game to you.

MM

So... what was that you said about Gravy's explanations, again?

[jaydeehess]

He seems to think that some how a surface's normal force is capable of changing directly proportional to the force acting on it... :faint:

-Gumboot

Which is exactly where the "ground pushs up" statement breaks down as MRC Hans points out.

The Earth's surface has an ability to resist the force on exerted by objects on it. This capability is related to the strength of the particular surface. A sand base would in no way be able to support the towers but granite bedrock can.

If the upward force exerted by the bedrock was always equivalent to the force exerted by the completed tower then any attempt to build the tower would have resulted in the partially completed tower accelerating into the air since that force would be greater than the force due to the mass of the partially completed tower. In fact if this were the case then as the tower did collapse and shed mass to the side the tower should have rose upwards.

The ability to resist the force of mass of objects on the surface of the Earth can indeed be overcome. Just put enough mass on one spot and it will sink into the bedrock but that would be a very large mass.

However this has no bearing on the collapse since the bedrock did not fail. The steel columns failed. they have a much lesser ability to resist the force of the mass on them. They are designed to take the force due to the gravity load of the portion of the building above them. There was another force involved in the collapse though, the impulse of the falling upper section. (actually there were a lot of ways the energy of the falling mass was used, this is one) The mass came down and acheived a certain velocity and thus a certain value of momentum. It acted upon the columns below which slowed the upper section by some degree. The force exerted on the columns would be the change in momentum divided by the time it took to reduce that momentum PLUS the force due to gravity.
I don't recall where I read it but it had been calculated that the columns would have deflected enough to snap only a few milliseconds after being hit by the falling mass that would be when the loss of momentum would stop.

[jaydeehess]

I see myriad explained things a lot better than I did. That's what i get for not reading the entire thread.

MM writes:
Too bad this post reveals an inability to explain the content. Cut and paste is easy, but explanations are obviously incredibly challenging when engineering is not the posters area of expertise.

I think the "mathematical dummy" part was easy to understand and I have to agree with that conclusion.

So did you read through Greening's paper yet MM? Inappropriate remark removed. Have you the mathematical ability to follow it? Marks is stating that with his relatively(that's relative to Greening's)mathematical knowledge he was still able to follow greening's calculations. Can you say the same? If so then please, by all means point out all the errors in math that Greening made and how they would be significant in determining the process of collapse. Then you can move on to B & Z's paper and do the same.

In fact you can come up with your own paper explaining when and where additional damage had to be inflicted on the buildings by incendiary heating and/or explosives in order to have the buildings collapse as they did.

[notheist]

Let me raise a somewhat different point that these guys seem to be missing. Constant motion is a sign of NO external force entering the system. Last time I checked wasn't that an extremely basic principle of physics?

I think its the idea something in motion will remain in motion until acted upon by an outside force.

[jaydeehess]

the velocity of an object will not change until acted upon by an external force.

Thus an object at rest remains at rest (velocity = 0), in relation to the frame of reference in which the object resides.

Its one of Newton's laws of motion.

[jaydeehess]

Has anyone suggested to this guy that he put a large physics text book on the top of his head, note the force due to gravity that it displays. Then take that book and suspend it 3 inches above his head then release it to drop onto his head and note the difference in the force he feels between that and the staic book on his head. Now he can explain why the force of the dropping book was so much greater than that of the dropped book.

Yes, momentum is not force but a change in momentum over time IS a force.

[maccy]

I've left a comment on his first video.

In your opening example of the ball dropping to the ground. Shouldn't the ball bounce?

How would you explain a bouncing ball in terms of your equal and opposing forces? Surely the ball should only have enough energy to fall?

Even though it's fairly subtle, I expect it'll be deleted (especially if he's reading this thread). Maybe it'll be a niggle that sticks with him and he gives some thought at a later date, when his ego is no longer involved.

I certainly believed a lot of stupid things in my teenage years. And I was sure I knew it all as well.

[T.A.M.]

Just how many times do you want it.

Or is it that you do not wish to know?

lol...I was adding my desire, along with gumboots, to have the science of it explained if possible, in relatively simplified Physics calculations...lol

I know it has probably been done before, but I havent seen it, although in this thread, it has been, somewhat, done...

TAM:)

[Totovader]

This has got to be the best of the Stundie, for May:

400 people have seen this video. 5 disagree enough to attempt to argue their points. 4 of those people are now blocked, as they had a fair go (20+ posts) and couldn't debunk me. I want to let some others have a go. That makes the deniers, or coincidentalists, approximately 1.25% of the youtube population, as depicted by the sample which has watched this video.

You are in the minority. Understand this. MINORITY. Public opinion IS AGINST YOU.

Not only is he bad at physics, but he fails at statistics as well.

[gumboot]

However this has no bearing on the collapse since the bedrock did not fail. The steel columns failed. they have a much lesser ability to resist the force of the mass on them. They are designed to take the force due to the gravity load of the portion of the building above them. There was another force involved in the collapse though, the impulse of the falling upper section. (actually there were a lot of ways the energy of the falling mass was used, this is one) The mass came down and acheived a certain velocity and thus a certain value of momentum. It acted upon the columns below which slowed the upper section by some degree. The force exerted on the columns would be the change in momentum divided by the time it took to reduce that.



Actually, watching the collapse, I suspect very little impact force was applied directly to the columns. I think that's one of the problems with the design that resulted in such a catastrophic collapse.

By nature of gravity, most of the collapsing mass fell inside the building's footprint (it had to). This means it was inside the exterior columns. We can see evidence of this in the fact that the exterior columns peel outwards as the collapse occurs. That means, immediately, half the mass-supporting structure is removed from the equation.

That leaves the core columns, but as we know the building twisted as it fell. That makes it highly unlikely that the core columns lined up.

Instead, the force of collapse was left on the light weight truss systems.

Designers of the WTC talked about aircraft impacts being like a pencil pushed through a mosquito net. I think that's a good analogy for what happened in the collapse. The lower core columns would easily punch through the floor trusses in the upper section, and the upper core columns would easily punch through the floor trusses in the lower section.

Consider the below very simplified collapse model:

http://forums.randi.org/imagehosting/10153463ffade65489.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=5594)

In this model, what is actually taking the force of the collapse? The columns?

-Gumboot

[~enigma~]

I think its the idea something in motion will remain in motion until acted upon by an outside force.
In other words constant motion is a sign that there was NO external force. Read your own post backwards and you'll see.

[~enigma~]

the velocity of an object will not change until acted upon by an external force.

Thus an object at rest remains at rest (velocity = 0), in relation to the frame of reference in which the object resides.

Its one of Newton's laws of motion.Correct and constant motion denotes nO external force. For example, say you go outsomewhere in space and you shoot a bullet with a muzzle velocity of say 3000 fps. If no outside force acts upon it, it will still be going 3000 fps in a year, decade, century and so on. Constant motion is a sign of no external force. Why do some people have such a hard time grasping that?

[~enigma~]

Has anyone suggested to this guy that he put a large physics text book on the top of his head, note the force due to gravity that it displays. Then take that book and suspend it 3 inches above his head then release it to drop onto his head and note the difference in the force he feels between that and the staic book on his head. Now he can explain why the force of the dropping book was so much greater than that of the dropped book.

Yes, momentum is not force but a change in momentum over time IS a force.
They (by they I mean the woo and the other truthers that believe this nonsense) think that the normal force is the be all and end all to woogic™.

[gumboot]

Correct and constant motion denotes nO external force. For example, say you go outsomewhere in space and you shoot a bullet with a muzzle velocity of say 3000 fps. If no outside force acts upon it, it will still be going 3000 fps in a year, decade, century and so on. Constant motion is a sign of no external force. Why do some people have such a hard time grasping that?



That's not entirely true. Constant motion can also be a result of external forces in equilibrium, just as a static position can also be a result of external forces in equilibrium.

for example when an object is sitting on the ground, not moving, but there are indeed forces acting on it - gravity and normal force.

It is accurate to say that an absence of external forces will mean zero change in momentum, however it is not accurate to claim, therefore, that zero change in momentum means no external forces.

This is a logical fallacy, called affirming the consequent.

I think what you mean is the net force is zero.

If there is no external force, net force is zero.

However if net force is zero that does not necessarily means there is no external force.

-Gumboot

[SYLVESTER1592]

Actually, watching the collapse, I suspect very little impact force was applied directly to the columns. I think that's one of the problems with the design that resulted in such a catastrophic collapse.

By nature of gravity, most of the collapsing mass fell inside the building's footprint (it had to). This means it was inside the exterior columns. We can see evidence of this in the fact that the exterior columns peel outwards as the collapse occurs. That means, immediately, half the mass-supporting structure is removed from the equation.

That leaves the core columns, but as we know the building twisted as it fell. That makes it highly unlikely that the core columns lined up.

Instead, the force of collapse was left on the light weight truss systems.

Designers of the WTC talked about aircraft impacts being like a pencil pushed through a mosquito net. I think that's a good analogy for what happened in the collapse. The lower core columns would easily punch through the floor trusses in the upper section, and the upper core columns would easily punch through the floor trusses in the lower section.

Consider the below very simplified collapse model
In this model, what is actually taking the force of the collapse? The columns?

-Gumboot

Nice model. Simple and effective if you keep it's limitations in mind.
:)

I imagine that would also help to explain why the top floors were destroyed so quickly during the collapse, as the central column would spear through the connections between the top floors and the columns as the top fell, increasing the asymmetry of the load. The top floors would have been destroyed at a distance about 14 and 24 floors down from the top...yes?

It would crash down along the remaining lower structure, despite the torsion and tilt of the top. It would do so at least initially since the center of gravity of the upper structure didn't pass beyond the perimeter columns and further down because the broken columns would slide past each other at a distance, but limiting a further movement of the center of gravity of the top towards the perimeter and tearing up the floors due to the twist and tilt of the upper structure. The total weight of the top floors would bear down on the severed columns (at least in the model), resulting in the columns to punch through the floors.

I'm simplifying of course and not sure if I'm right,..
The discussion if you want to choose Wierzbicki's or Bazant's explanation for floor support failure, may be relevant here...
Need some help on that one. I would have to read the posts and the papers a few times over again.

:confused:

[gumboot]

Nice model. Simple and effective if you keep it's limitations in mind.
:)

I imagine that would also help to explain why the top floors were destroyed so quickly during the collapse, as the central column would spear through the connections between the top floors and the columns as the top fell, increasing the asymmetry of the load. The top floors would have been destroyed at a distance about 14 and 24 floors down from the top...yes?

It would crash down along the remaining lower structure, despite the torsion and tilt of the top. It would do so at least initially since the center of gravity of the upper structure didn't pass beyond the perimeter columns and further down because the broken columns would slide past each other at a distance, but limiting a further movement of the center of gravity of the top towards the perimeter and tearing up the floors due to the twist and tilt of the upper structure. The total weight of the top floors would bear down on the severed columns (at least in the model), resulting in the columns to punch through the floors.



Yeah, that's pretty much my thoughts.

Bear in mind that the core columns themselves are also made up of welded segments 3 stories high. In the diagram I provide they're not exposed to much compression force (relatively speaking) however the collapse would no doubt exert a lot of random lateral force against them as the buildings rip apart. As such one can expect the upper section column welds to break apart during the collapse, and probably the top of the lower section columns as well.

In an ideal situation NIST or someone else would have marked where every single column and exterior panel landed (they were all labeled). This sort of data would have been invaluable, and with it NIST might have even been able to produce a rough model of the collapse progression.

However at the time as many as 7,000 people (or more) were feared trapped in the rubble, and the priority was recovering them.

-Gumboot

[qarnos]

What I find interesting about all this is exactly how the truthers came to this point - trying to prove progressive/pancake collapse is impossible:

They see the "squibs". This must mean there were bombs on every floor.

Then a debunker comes along and says, "why on Earth would they put bombs on every floor - that is unnecessarily complicated."

Hmm... thinks the truther. This must mean that progressive/pancake collapse is impossible!

So now they spend their time using warped physics and the "soda can tower" to "prove" their point.

The lies just keep snowballing.

[Totovader]

Oh my...

Well, that's it fellow NWO members. He's "debunked the debunkers"

sBfkAzWbnvM

He's managed to figure out that if the core columns would have "buckled" (his strawman), that the entire building would have bent like a big "C"...

Absolutely amazing.

[westprog]

Oh my...

Well, that's it fellow NWO members. He's "debunked the debunkers"

sBfkAzWbnvM

He's managed to figure out that if the core columns would have "buckled" (his strawman), that the entire building would have bent like a big "C"...

Absolutely amazing.

Well, he's convinced me. The net force is zero, simple Newtonian physics, he's given the debunkers a fair shot at it.

What I like is the way that the voice gets higher as he hits a really dubious bit of reasoning as he needs to convince himself.

In the second half, he explains that if we treat the beams on a per floor basis, then they would have to have bowed symmetrically, and hence held up the building BECAUSE THE FORCES ARE EQUAL. He then switches to a picture showing the top of the building at a considerable angle. By then he's already forgotton the reasoning he was using before.

[AZCat]

Oh my...

Well, that's it fellow NWO members. He's "debunked the debunkers"

sBfkAzWbnvM

He's managed to figure out that if the core columns would have "buckled" (his strawman), that the entire building would have bent like a big "C"...

Absolutely amazing.

His strawman is breathtaking in its stupidity. Who ever argued that the buildings would fail like that (at least, who in their right mind)?

[gumboot]

I love where he says and alternative reaction from the building if the core columns shattered was that the building would start to collapse from the bottom.

So basically he's saying it has to be a controlled demolition, because if it wasn't a controlled demolition, it would look like one.

Un-[rule8]-ing Believable.

-Gumboot

[Totovader]

If you notice- he does debunk himself, however. He admits that he's not saying the building wouldn't fall- as he tries to move the goalpost to regress his argument to the "net force is zero" claim- and claim that you can't argue with Newtonian Physics (and coincidentally, anyone who does is a fool). He claims that people are using strawmans against him when they claim that he is asserting the building wouldn't fall. Never mind that this has been his clearly stated position the whole time.

That's a sign that he's figured out his error. Of course- he just dives right back into it. Every other statement he's made completely contradicts this; his next statement about the explosives in the upper part of the building "as it's falling" expose his position as being a bit more than just "the net force is zero".

I know he reads this- and since he's blocked everyone who disagrees with him: You can't have it both ways, bud. You cannot claim on the one hand that you aren't making any specific statements about the collapse, and then turn around and make very specific statements about the collapse. You're debunking yourself.

[Horatius]

But at least he gave a shout-out to the JREF forum!

So once again, a twoofer is inadvertently pointing people to a good place to learn some actual physics.

And it's nice to see, that in "acknowledging" that the buildings had structure, he manages to forget that the core columns were also a complex structure. There's simply no way they could have buckled along their whole length like he shows, as they would have snapped at the weld points along the length. And of course, his claim that that's the model we're promoting is a pure strawman.

Not to mention, his concept that they should have buckled at the "point of maximum leverage" ignores the structure of the floor trusses, which were designed to prevent just exactly that sort of buckling.


The really sad part is, with his "buckling of each floor" argument, he's almost got it right. Yes, each floor would fail in series. Yes, each floor would absorb some energy in doing so. The problem is, he asserts, without any proof or analysis, that such absorbtion would be enough to stop the upper block. And that's where he loses it.

You simply cannot make that assertion without some supporting calculations. Stick figures on a video don't count. He says he knows physics so well, so lets see the math. Without actual math, he's just blowing smoke (and actually hand-waving, nice touch).

We've got papers that show such calculations, and they show he's wrong. so where is his math?

He's also made the claim that "his only claim" is that the upper block could not have accelerated, as the net force is zero. Well, the net force wasn't zero. If he claims it was, he needs to do a lot more than draw pictures and wave his hands to show that.

Oh, but there I go again, misusing my freedom! Bad, bad JREFer!

[JamesB]

This guy is hilarious. That is one of the funniest things I have seen in a while. They don't understand how entertaining they are as parodies of themselves.

[SYLVESTER1592]

What I find interesting about all this is exactly how the truthers came to this point - trying to prove progressive/pancake collapse is impossible:

They see the "squibs". This must mean there were bombs on every floor.

Then a debunker comes along and says, "why on Earth would they put bombs on every floor - that is unnecessarily complicated."

Hmm... thinks the truther. This must mean that progressive/pancake collapse is impossible!

So now they spend their time using warped physics and the "soda can tower" to "prove" their point.

The lies just keep snowballing.

NIST NCSTARCollapseofTowers Ch 5.3.6 p63 describes a smoke purge system that stretched over several floors. NIST NCSTAR 1-5 Chap 1.1 p57 describes how the ventilation system was damaged and explained how smoke could travel, but it was not fully modeled.
NIST NCSTAR 1-5 Chap 4.2 description of the fire dynamics simulator p124 describes the boundaries for the model. Here they mention the presence of HVAC air-conditioning and ventilation ducts. I would expect the traveling debris and dust cloud to be funneled through these ducts. Dust in these ducts would travel at a higher velocity then the debris and dust cloud that pressurized it, much like a bicycle pump...

NIST NCSTARCollapseofTowers Ch 8.5.3 Fire Safety, explains that there was no "fire tower" (staircase with natural ventilation) so that would basically exclude the staircases as a funnel for the debris regarded as "squibs"
Exiting the building, I guess the dust from these ducts could have been mistaken for "squibs".

It's not easy to find a plan which shows the exact layout of the ducts. The Port authority probably has them, but I think the statement that "there is no other explanation then explosives" can be refuted.

The "soda can tower", actually does buckle inward and twists as it crushes. There are however two main problems: they don't weigh much and carry a very large load (compared to their own weight). Most people don't realize that the towers were built to withstand forces that were relatively small compared to the support of the structure itself. When the tower itself started to collapse, the force distribution and energy of the collapse far exceeded any purpose of the buildings design. People think you try to fool them by presenting a rickety structure, when in reality you show them a structure that is mainly concerned with maintaining it's own integrity in the presence of relatively small external forces. It's very hard to present an analogy that will explain that convincingly to someone using only "common sense". Of course there are people that just don't want to understand.

I'm not defending it, but I understand the mistake...and the frustration it evokes.
:)

[westprog]

He's also made the claim that "his only claim" is that the upper block could not have accelerated, as the net force is zero. Well, the net force wasn't zero. If he claims it was, he needs to do a lot more than draw pictures and wave his hands to show that.

He's plainly shown that the net force was zero, because if it wasn't zero, the building would be collapsing. The building couldn't be collapsing because the Net Force Was Zero. :w2: IT'S SIMPLE ***ING NEWTONIAN PHYSICS!

At least in the sense that his arguments are in a simple orbit. I think he's using his conclusions to prove his assumptions, but the reasoning is so unclear that it's very difficult to see what he's getting at. It's obviously very, very wrong, but getting a clear argument that can be dismissed isn't easy.

[jaydeehess]

Actually, watching the collapse, I suspect very little impact force was applied directly to the columns. I think that's one of the problems with the design that resulted in such a catastrophic collapse.

By nature of gravity, most of the collapsing mass fell inside the building's footprint (it had to). This means it was inside the exterior columns. We can see evidence of this in the fact that the exterior columns peel outwards as the collapse occurs. That means, immediately, half the mass-supporting structure is removed from the equation.

That leaves the core columns, but as we know the building twisted as it fell. That makes it highly unlikely that the core columns lined up.

Instead, the force of collapse was left on the light weight truss systems.

Designers of the WTC talked about aircraft impacts being like a pencil pushed through a mosquito net. I think that's a good analogy for what happened in the collapse. The lower core columns would easily punch through the floor trusses in the upper section, and the upper core columns would easily punch through the floor trusses in the lower section.

Consider the below very simplified collapse model:

http://forums.randi.org/imagehosting/10153463ffade65489.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=5594)

In this model, what is actually taking the force of the collapse? The columns?

-Gumboot


That is actually more along the lines of what I could envision occured as well.
It adds to my idea that the peeling away of the perimeter columns was a result of the mass falling through and filling up the space between the perimeter columns. Pour sand into a milk carton and the sides bulge outward indicating an outward force. Dump that sand in very quickly and the force on the sides increases, have it enter that carton fast enough and the seam of the carton will fail. As the upper section fell, all that debris would still be falling into the space between the perimeter columns at great velocity, filling the floors and exerting an outward force on the perimeter column trees.

That outward force is the result of the downward movement of the debris being slowed by the resistance of the floors. As the floors offered some resistance to the falling debris that debris piled up inside the perimeter, this forces the perimeter columns outward, once the impulse force and gravitational force of the mass fails the floor(this would happen very quickly since the floors were designed to transfer only the load of the mass of the objects on each floor , not a significant percentage of the mass of the entire building) that severs the lateral support on the perimeter trees which are then ejected outward.


I note that the twoof expected that the upper section would topple over to one side. I would ask him what force would be present that would cause the upper section to select a preferred direction to fall. In his drawings he has that the initial collapse would be assymetrical and indeed it would but he expects that the higher side of the lower section would act as a pivot point and cause the upper section to rotate, or he expects that it would result in an inclined plane that would see the upper section slide off.

In the firstcase, the upper section toppling over, the force on the pivot would very quickly crush it once again resulting in a more vertical fall. Now that the upper section is no longer pivoting, the rotation occurs about its ceter of mass rather than the pivot point. Unless that center of mass gets beyond the perimeter of the building the bulk of the mass of the upper section IS STILL falling inside the perimeter columns!

In the second case, the upper section sliding along an inclined plane, this is patently ridiculous. As soon as the columns do not line up they fall through the space between columns. Even that assumes that the columns could slide apart at all. More likely they are buckling and all they need do is buckle to a point where they can no longer resist the vertical force on them and they will then shear off at the buckled section once again resulting in a vertical fall.

[jaydeehess]

At the time of collapse initiation the coulmns could no longer 'push back' enough to support the load. Thus at that time the net force is NOT zero and thus the uppersection begins it downward movement as a result of that imbalance. It gains momentum in this way. If the lower section can arrest all of this momentum then the upper section will only offer the force due to its mass on whatever it is resting upon(which as pointed out above, is unlikely to be the columns). If it could not arrest all of that momentum then it would still have some velocity from its initial fall and that would add to any increase in velocity as it fell through the collapsed next floor space which would mean that it contained greater momentum than it did in the initial collapse. If the first impact after initial collapse could not arrest that value of momentum and the upper section had not shed enough mass to make its momentum smaller than at the first impact, then the next floor can hardly be expected to arrest a greater momentum than the first impact.

That momentum is absorbed over the time of each impact and the distance it travels during that time. This gives the us energy absorbed (IIRC). The energy the floors can absorb is basically fixed but the energy available due to the falling mass goes up in proportion to the square of the velocity even though the momentum is only directly proportional to velocity.

[gumboot]

It's funny; the CTers like to talk about the "massive" core columns. I think part of the problem is, they have no understand of what "massive" in building terms means.

In the area around the collapse zones, the very largest core columns were about 0.55m square. Even assuming all 47 core columns were of the box-weld shape (they weren't) and all of the largest size (they weren't), and solid steel (they weren't) you're only talking a cross section (combined) that's 14.2m2, or 0.35% of a given floor's total area.

Even if you add the 240 exterior columns (0.355m x 0.355m) and assume they are solid (again, they weren't) you still get less than 45m2 of total column cross section, or 1.1% of the floor's total surface area.

This is why enormous buildings can stand, but when something is taken out of whack the result is catastrophic. It's a careful balancing act.

I recall once someone said if superman tried to catch the falling towers in midair by grabbing hold of one core column, it would simply rip the building apart and the thing would keep falling down, with superman left sheepishly holding a single piece of column.

Even if the upper mass perfectly landed on the core columns somehow, a similar thing would have happened. The exterior columns were undermined by the failure, and the core columns cannot hold the building on their own. The floor trusses and exterior columns of the upper mass would have ripped free of the core columns, and smashed through the bottom of the tower with the same result we saw on 9/11.

As it turns out, the building had to only shift half a meter in any direction, and those columns would no longer line up.

I think the exterior column idea, with no internal spaced columns, was part of the fatal design for the WTC, given a collapse scenario.

Essentially, the structural integrity of the entire structure ended up relying on the very weakest element in its entire structure - the fixtures that held the floor trusses to the core columns and exterior column spandrel plates.

Far as I can tell, each truss was connected to a thin ledge on the spandrel and bolted in place. On the interior the truss was attached to the frame, with bolts attaching to channels welded to each core column.

In all, with exterior fixtures on every second column, that's 116 exterior fixture points and 26 interior fixture points. And that's it.

The irony is, of course, the collapse was initiated because those exact some fixture points in the impact zone didn't fail.

So the floor truss connections twice-doomed the towers.

-Gumboot

[jaydeehess]

The irony is, of course, the collapse was initiated because those exact some fixture points in the impact zone didn't fail.

So the floor truss connections twice-doomed the towers

Interesting take on that. The truss seats do not fail under the stress of the sagging floors thus allowing that stress to bow in the perimeter columns which themselves fail and which then would have required that the floor truss seats on the next intact floor be able to take the weight and impact of the upper section in order to halt collapse.

how's physics boy holding up to his critics?

[beachnut]

Oh my...

Well, that's it fellow NWO members. He's "debunked the debunkers"

sBfkAzWbnvM

He's managed to figure out that if the core columns would have "buckled" (his strawman), that the entire building would have bent like a big "C"...

Absolutely amazing.Is he trying to be nuts? He actually debunked himself a few times.

Do his followers know his physics is out to lunch? Are they all dropouts?

OMG, there is a whole nest of people who are supporting the new UTube physics fraud. Cool. How do people get to be so challenged and unable to understand physics, or take the time to gather knowledge. The UTube physics teacher is funny, his Sam Kinison routine at the end is GREAT. I wish he would just do the physics rant he does at the end for a whole tape, like Sam would do.

[Vincent Vega]

Its the case of "a little information making one dangerous". The one thing that truthers have in common is their missunderstanding of the energy and forces involved.

I've tried to explain that energy is energy whether it is chemical or kinetic. And the energy involved in moving masses as large as the WTC are just not applicable to everyday experiences, which is where most "Woo-Fiziks"
originates from...beter known as "common sense".

[Totovader]

<snip>

how's physics boy holding up to his critics?


What critics?

He just blocks them all and removes their comments. Problem solved.

[beachnut]

What critics?

He just blocks them all and removes their comments. Problem solved.
He could do comedy physics, but has chosen to do censor-NAZI.

I still think if he added some more "Sam Kinison" type rant, he could make money selling his physics class for the physics challenged engineering dropouts.

I hope he does one solid rant video, it is cool how I start believing gravity stops as he rants. I was floating all over the house. The Titanic never sunk, and the WTC never fell. What is next, I will never fall through rotten floors because the ground is pushing up. I always wanted to meet the ground and thank him for pushing up.

[westprog]

And the energy involved in moving masses as large as the WTC are just not applicable to everyday experiences, which is where most "Woo-Fiziks"
originates from...better known as "common sense".

It isn't that difficult though. Most people understand the analogy of resting a bowling ball on a glass table, and then dropping it from six feet above. When it's explained that the top of the building was falling and whacking into the floors below, most people intuitively get the idea of what happened. In order to not get it, it's necessary to have no intuitive feel for the physics, and the capacity to misabsorb some ideas from random areas of physics.

In this case, he's convinced himself that forces must always be exactly balanced. If that were really the case, then all motion would be impossible. As with most CT thinking, he hasn't correctly applied his own mistaken ideas, and hasn't thought through the implications. If it really were the case that the forces were in exact equilibrium, it would have been impossible to destroy the building under any circumstances.

[T.A.M.]

He is the Charles Schultz of 9/11 denial.

oh boy....that is just bad.

TAM:)

[twinstead]

I always wanted to meet the ground and thank him for pushing up.

I just got an email from the ground. He says your welcome...

[Totovader]

It isn't that difficult though. Most people understand the analogy of resting a bowling ball on a glass table, and then dropping it from six feet above. When it's explained that the top of the building was falling and whacking into the floors below, most people intuitively get the idea of what happened. In order to not get it, it's necessary to have no intuitive feel for the physics, and the capacity to misabsorb some ideas from random areas of physics.

In this case, he's convinced himself that forces must always be exactly balanced. If that were really the case, then all motion would be impossible. As with most CT thinking, he hasn't correctly applied his own mistaken ideas, and hasn't thought through the implications. If it really were the case that the forces were in exact equilibrium, it would have been impossible to destroy the building under any circumstances.

Exactly. Due to the fact that conspiracists often seek to confirm their predetermined conclusions, they often put their foots in their collective mouths when they attempt to cross over into the realm of science. When they do this, they must stop short of any calculations or actually completing their assertions, because their failed logic quickly shows them how wrong they are... They avoid the scientific method like the plague.

This is really no different than Judy Wood or Steven Jones.

As you said- if his assertions were true... then movement would be impossible. And challenging their own positions is just absolutely unheard of in the conspiracists realm.

This is precisely the reason he tried to backtrack and claim that others are strawmanning his argument when they challenge the statements he's made about the collapse itself- he tries to backtrack and refocus his claims to the utterly simple "zero net force" claim and only that (despite the fact that 2 seconds later he contradicts it).

There's so many fallacies in his statements it's difficult just narrow it down to simple error. It's a pattern of irrational thinking.

[SYLVESTER1592]

There is one good side to all of this: CT'ers are now reading JREF.
Now, if any of this sinks in, eventually some of them must get it.

[Horatius]

There is one good side to all of this: CT'ers are now reading JREF.
Now, if any of this sinks in, eventually some of them must get it.



They're so cute when they're young. We'll beat that out of you :)

[Vincent Vega]

It isn't that difficult though. Most people understand the analogy of resting a bowling ball on a glass table, and then dropping it from six feet above. When it's explained that the top of the building was falling and whacking into the floors below, most people intuitively get the idea of what happened. In order to not get it, it's necessary to have no intuitive feel for the physics, and the capacity to misabsorb some ideas from random areas of physics.

In this case, he's convinced himself that forces must always be exactly balanced. If that were really the case, then all motion would be impossible. As with most CT thinking, he hasn't correctly applied his own mistaken ideas, and hasn't thought through the implications. If it really were the case that the forces were in exact equilibrium, it would have been impossible to destroy the building under any circumstances.

I am refering to the usual claim that to have occur what we witnessed (violent expulsion of debris during the collapse) there would have to have been explosives on every floor.

[Furcifer]

It isn't that difficult though. Most people understand the analogy of resting a bowling ball on a glass table, and then dropping it from six feet above. When it's explained that the top of the building was falling and whacking into the floors below, most people intuitively get the idea of what happened. In order to not get it, it's necessary to have no intuitive feel for the physics, and the capacity to misabsorb some ideas from random areas of physics.


Yep. It's the ones that don't have any intuition that inherently ask "So the building was made of glass?" They are totally incapable of resolving this analogy. It in variably becomes "I'm too smart for you, i know the building wasn't made of glass."

[pomeroo]

I'll return to your sandbox tomorrow beachnut.

MM



After observing them closely for a year, it still amazes me that fantasists are absolutely impervious to knowledge. R. Mackey painstakingly dissected--in exhaustive detail--your sophistries regarding the landing gear in the Twin Towers. Your sciolism having been laid bare, you return to make sneering comments to someone else who knows vastly more about technical subjects than you do.

[Minadin]

This is pretty amazing stuff. Has anyone else seen this one?

_SxyK5Hea8w

He's trying to model the collapse of the towers using (empty) coke cans. It's reminiscent of the glued together egg model.

I'm trying to decide if the guy is a real believer or just putting on a routine.

[Horatius]

This is pretty amazing stuff. Has anyone else seen this one?

_SxyK5Hea8w





Fixed the youtube link for you.

[gumboot]

*head asplode*

...

Must...not...break...monitor...

-Gumboot

[Horatius]

Having fixed the link, I've now watched the video. Wow. He doesn't want computer sims, as they are unrealistic, but he's okay with diet Coke cans?

We should link him to the chicken wire guy, where he figured out that his model was several hundred times stronger (relatively speaking) than the WTC, because he underestimated the scaling factors.

It's the effect of scaling that these guys (call them modelers) don't get. Of course he figures the biggest problem is that he hasn't set the whole thing on fire!

This is just another examle of a twoofer who can't do science. Part of science is recognizing the limitations of your models and experiments, but he simply cannot figure out where the limits of his model are. His attempts to do that are all pretty pathetic, and in most cases, he argues that the limits are in the favour of the official story, which simply isn't true.

On another note, most people don't realize exactly how strong those cans are in compression. If there are no dents or flaws in the sides of the can, they can hold up a heck of a lot of weight. Back in high school, just a few years after they were introduced into our area, I used to impress people by balancing a person on one of these. If they didn't wobble too much, the can would hold their weight quite well. People would ohh and ahh - then I'd give a small flck to the side of the can, and it would fold up almost instantly. Just a bit of a flick was enough to destroy the integrity of the structure! But while it holds, the strength to weight ratio is ridiculously high!

I think I'll make a video of that, and post it too him......I just need a cute girl who won't mind me posting her weight on the interweb.....I suppose I could settle and use bricks....

[Disbelief]

I can't watch at work, but I am reminded of a thread over at LCF. They were talking about critical temperature and how the steel would vaporize, laughing at what an expert was writing about. Of course, they never realized that they had wiki'd critical temperature of gasses and had no idea what it meant for steel.

[maccy]

Also, from one of his earliest defenders, perhaps this:

KDHN1gBkx0M

was his inspiration?

It is a rare example of a Conspiracy Fantasist trying to be funny. I think he scores slightly higher than Kevin (http://screwloosechange.blogspot.com/2007/04/barretts-humor-falls-flat.html) Barrett (http://screwloosechange.blogspot.com/2007/04/more-humor-from-kevin-barrett_15.html).

We have to deduct points for banging on about common sense (http://forums.randi.org/showthread.php?t=71774), though.

[Totovader]

This is pretty amazing stuff. Has anyone else seen this one?

_SxyK5Hea8w

He's trying to model the collapse of the towers using (empty) coke cans. It's reminiscent of the glued together egg model.

I'm trying to decide if the guy is a real believer or just putting on a routine.

I was waiting to post that one because I figured I have over-extended my YouTube posting for this week... but this is absolutely hilarious.

He's a real believer- even then I wondered, though. Burnvictim77 and I have both dealt with his claims before, and like this latest woo-aholic, he just blocks people who disagree with him. In one case he made such egregious errors that he made his videos private because Burnvictim77 had exposed some flat-out lies in his statements.

Perhaps the funnest thing of all is watching these conspiracists go through the process of cognitive dissonance. I know it's kind of like poking them with a stick- but it's hard to back off when you get such classic comedy like the "pop-can as a model for the Twin Towers" stuff. I just can't help but put more quarters in the machine...

I spend so much time laughing- though- that I'm a bit disillusioned when I see that people actually believe it.

[gumboot]

Yeah I noticed that too Horatius... the bit about "no computer models, it's not realistic...here's a diet coke can" :faint:

To be fair, I don't think scaling is this guy's problem. The chicken wire guy at least tried to represent the structure, as did the paper tower guy.

This guy is using FIVE COKE CANS.

It would be kind of funny to do a strength to weight ratio for a coke can and extrapolate from that how much weight the WTC "should" be able to hold.

I imagine it would be obscenely heavy.

-Gumboot

[gumboot]

Also, from one of his earliest defenders, perhaps this:

KDHN1gBkx0M

was his inspiration?

It is a rare example of a Conspiracy Fantasist trying to be funny. I think he scores slightly higher than Kevin (http://screwloosechange.blogspot.com/2007/04/barretts-humor-falls-flat.html) Barrett (http://screwloosechange.blogspot.com/2007/04/more-humor-from-kevin-barrett_15.html).

We have to deduct points for banging on about common sense (http://forums.randi.org/showthread.php?t=71774), though.


*cries*

-Gumboot

[Horatius]

This guy is using FIVE COKE CANS.

It would be kind of funny to do a strength to weight ratio for a coke can and extrapolate from that how much weight the WTC "should" be able to hold.

I imagine it would be obscenely heavy.

-Gumboot



That's my plan. I've decided I will make a video of a can holding up a heck of a lot of weight. It'll take a bit of time, but I'll get to it. Hopefully this week, as I'm off on vacation soon after that.

I'll need to scrounge up a good set of balances, to weigh the can. I've got some bricks lying around, which I'm pretty sure won't be enough to crush the can. That and a video camera, and I'm set!

[Minadin]

Ok, I'll admit I'm totally ignorant about how to do a You-Tube link. How did you fix it?

[gumboot]

If you look at the YouTube links they will end in v=FKHG24G or something. Take the bit after the "v=" (so just the last series of numbers/letters) and put it in a YouTube tag (yt) (/yt), but square brackets [] obviously.

-Gumboot

[Horatius]

Ok, I'll admit I'm totally ignorant about how to do a You-Tube link. How did you fix it?



Like Gumboot said. Try quoting someone who has a working link, and you'll see the formating.

[slyjoe]

From Gumboot's sig:

"My see-saw analogy renders any need for "calculations" moot." - Lyte Trip

How about this corrollary:

"My diet coke can demonstration renders computer simulation unnecessary" - YouTube moron.

[Vincent Vega]

This is pretty amazing stuff. Has anyone else seen this one?

_SxyK5Hea8w

He's trying to model the collapse of the towers using (empty) coke cans. It's reminiscent of the glued together egg model.

I'm trying to decide if the guy is a real believer or just putting on a routine.

This guy reminds me of
http://www.jesseshunting.com/forums/html/avatars/bill-murray-carl-caddyshack.jpg
"Licenced to kill gofers by the government of the united nations"

[Vincent Vega]

Also, from one of his earliest defenders, perhaps this:

KDHN1gBkx0M

was his inspiration?

It is a rare example of a Conspiracy Fantasist trying to be funny. I think he scores slightly higher than Kevin (http://screwloosechange.blogspot.com/2007/04/barretts-humor-falls-flat.html) Barrett (http://screwloosechange.blogspot.com/2007/04/more-humor-from-kevin-barrett_15.html).

We have to deduct points for banging on about common sense (http://forums.randi.org/showthread.php?t=71774), though.

The towers below the collapse was "bigger" than the part above the collapse...so's it should have "bounced off". Fu#King unreal.

[Furcifer]

This is from episode one of "Beavis, Butthead and Bill Nye; The Science Guys" A short lived Nickelodeon spin off. Sadly, Bill Nye pulled out before the the first taping, leaving Nickelodeon under contract for three episodes. Episode 2: " Perpetual Motion, What the Government Doesn't Want You to Know" and Episode 3 : "The Moon, Friend or Foe?"

[SYLVESTER1592]

I was waiting to post that one because I figured I have over-extended my YouTube posting for this week... but this is absolutely hilarious.

He's a real believer- even then I wondered, though. Burnvictim77 and I have both dealt with his claims before, and like this latest woo-aholic, he just blocks people who disagree with him. In one case he made such egregious errors that he made his videos private because Burnvictim77 had exposed some flat-out lies in his statements.

Perhaps the funnest thing of all is watching these conspiracists go through the process of cognitive dissonance. I know it's kind of like poking them with a stick- but it's hard to back off when you get such classic comedy like the "pop-can as a model for the Twin Towers" stuff. I just can't help but put more quarters in the machine...

I spend so much time laughing- though- that I'm a bit disillusioned when I see that people actually believe it.

This is the new strategy for thruthseeking. Ban and pick.

First the physics guy banned me and now the diet coke guy banned me and removed my post answering his "If it is real physics, it is testable". So if we can't model it, it's not physics?
:eye-poppi
Someone should introduce him to Stephen Hawking.
If you tell him make sure he knows the difference between Steven Jones and Stephen Hawking. :D

Anyone that hasn't been banned by a thruther yet, isn't trying hard enough. These guys want science, but no peer-review, what does that tell you.
:rolleyes:

[T.A.M.]

The coke can guy ...OMG

DOES HE REALIZE HOW FU&KING STUPID HE IS.

What more can i say...

TAM

[Minadin]

If I was going to try to model the towers to test their collapse, using only common household items, I would probably use stainless steel tableware. Lots of it too, since you need to have a fairly complex lattice if you're going to do this properly. Forks could be used to represent the exterior columns, butter knives for the interior core columns. Bewteen the butter knives and the forks, place a spoon to act like sections of floor trusses. If I wanted to get really elaborate, a cloth napkin draped across the top of the spoons could represent the floors.

Each piece would need to be very carefully soldered to the others with a tiny bit of solder to make them stay together. Once the "structure" is built and I'm confident that it's more or less accurate, for what it's worth, I could take about 1/4 to 1/3 the amount of loose silverware I used originally, which I'd thoughtfully placed aside, and dump it out of a box onto the top of my "tower".

What do you think would happen?

[Horatius]

What do you think would happen?




We would all die laughing.

[SYLVESTER1592]

It's not easy to find a plan which shows the exact layout of the ducts.

:)

Sorry,
:blush:
found it: NIST NCSTAR1-4 Chap 5
Everything still fits.

[tsig]

lol...I was adding my desire, along with gumboots, to have the science of it explained if possible, in relatively simplified Physics calculations...lol

I know it has probably been done before, but I havent seen it, although in this thread, it has been, somewhat, done...

TAM:)

Ok, The kenetic energy was greater than the existing ability

[T.A.M.]

Ok, The kenetic energy was greater than the existing ability

lol...i said calculations damn it.

you you...stop pulling my leg you...

TAM;)

[Myriad]

If I was going to try to model the towers to test their collapse, using only common household items, I would probably use stainless steel tableware. Lots of it too, since you need to have a fairly complex lattice if you're going to do this properly. Forks could be used to represent the exterior columns, butter knives for the interior core columns. Bewteen the butter knives and the forks, place a spoon to act like sections of floor trusses. If I wanted to get really elaborate, a cloth napkin draped across the top of the spoons could represent the floors.

Each piece would need to be very carefully soldered to the others with a tiny bit of solder to make them stay together. Once the "structure" is built and I'm confident that it's more or less accurate, for what it's worth, I could take about 1/4 to 1/3 the amount of loose silverware I used originally, which I'd thoughtfully placed aside, and dump it out of a box onto the top of my "tower".

What do you think would happen?

It depends on how you apply the tiny bits of solder. If you try to use a solder gun or iron, the tiny drops of solder won't wet the flatware and it'll probably start collapsing when you try to build the third storey. If you use a proper torch, then the thing will be strong and rigid enough to climb on, and you'll become a critically acclaimed sculptor.

Don't use lead solder if you plan to continue using the flatware.

Respectfully,
Myriad

[Disbelief]

If I was going to try to model the towers to test their collapse, using only common household items, I would probably use stainless steel tableware. Lots of it too, since you need to have a fairly complex lattice if you're going to do this properly. Forks could be used to represent the exterior columns, butter knives for the interior core columns. Bewteen the butter knives and the forks, place a spoon to act like sections of floor trusses. If I wanted to get really elaborate, a cloth napkin draped across the top of the spoons could represent the floors.

Each piece would need to be very carefully soldered to the others with a tiny bit of solder to make them stay together. Once the "structure" is built and I'm confident that it's more or less accurate, for what it's worth, I could take about 1/4 to 1/3 the amount of loose silverware I used originally, which I'd thoughtfully placed aside, and dump it out of a box onto the top of my "tower".

What do you think would happen?

Wouldn't you need flour or sugar for the "pulverized" or "dustified" concrete?

[beachnut]

This is the new strategy for thruthseeking. Ban and pick.

First the physics guy banned me and now the diet coke guy banned me and removed my post answering his "If it is real physics, it is testable". So if we can't model it, it's not physics?
:eye-poppi
Someone should introduce him to Stephen Hawking.
If you tell him make sure he knows the difference between Steven Jones and Stephen Hawking. :D

Anyone that hasn't been banned by a thruther yet, isn't trying hard enough. These guys want science, but no peer-review, what does that tell you.
:rolleyes:
It tells me, dolts who practice physics after one class in high school, even making an A, should not design high rise buildings. This kid was probably 13 or younger when the WTC was hit.

I was erased and banned. He is just like JDX, a censor NAZI, he has to answer the stuff and can not ignore it, kind of proves him wrong by default. He will now only have idiot posts to help his world of woo.

[beachnut]

He is holding court and teaching a new form of NET FORCE ZERO physics.

(note from a rational being)Total nonsense. Place an egg on the ground and drop a brick on top of it. By your NetForce=0 argument the egg won't break because the egg (being attached to the ground) matches the downward acceleration.

Answer from Yandros42 Physics Dolt--
No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero. The kinetic energy built up by the falling brick will most certainly shatter it. But if you were to take high speed recording of the brick smashing the egg you would find that the brick was not gaining velocity as it smashed the egg.

I am not sure why the brick hitting the egg will not accelerate, unless the egg is made of something harder than the brick.

So I set out to test young Yandros42 new zero force, no acceleration theories in my own beachnut testing grounds.

I found an egg made of stone. I put egg on ground, gee young Yandros42 was right, the ground pushes up and the stone egg floats on a earth of sandy soil. Wow, yandros42 is right. Next the brick. I take brick and drop brick from a height unmeasured as of yet, but a height not the less. Or was it less the not. Drop brick it accelerated at 9/8 m/s*s it was amazing, but it hit the egg. As it hit the egg it seemed the initial impact velocity was a value x, and the instant it hit the egg, the egg started to move down (into the sand) at a new speed very close to x but it look like the speed was still consistent with the total initial momentum minus just a little energy missing. OMG, the brick is accelerating with the egg into the sandy soil, then it stoped.

Yandros is wrong, the brick did have a new velocity but it continued to accelerate until it was slowed by the ground impact after neatly driving the egg into the ground. That egg took off into the ground.

Now the real egg, not cooked not stone.

Wow, the brick barely changed speeds as it crushed the egg. The brick as it touched the egg continued to accelerate until the ground slowed it. What do I do with a sandy egg mess? Will cats eat fried egg on sand?

I have come to the conclusion something is wrong with Yandros42 new found physics ideas. They fell apart like a brick crushing an egg.

[Belz...]

I recall once someone said if superman tried to catch the falling towers in midair by grabbing hold of one core column, it would simply rip the building apart and the thing would keep falling down, with superman left sheepishly holding a single piece of column.

IMPOSSIBLE. Superman would... er... his personal... protective shield would extend around the thing he held! Yeah! That's it!

[Horatius]

No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero. The kinetic energy built up by the falling brick will most certainly shatter it. But if you were to take high speed recording of the brick smashing the egg you would find that the brick was not gaining velocity as it smashed the egg.



It seems to me he's finally made a testable prediction.

Anyone got a high speed camera, a brick and some eggs they don't like?

[beachnut]

It seems to me he's finally made a testable prediction.

Anyone got a high speed camera, a brick and some eggs they don't like?
Me got brick and bunch of eggs.

The golf ball will be a solid stone type egg

http://forums.randi.org/imagehosting/124474641fda7dddd4.jpg

[rwguinn]

It seems to me he's finally made a testable prediction.

Anyone got a high speed camera, a brick and some eggs they don't like?
If he is using velocity as most of his ilk do, i.e. speed, he wolld be correct. it doesn't gain SPEED. IT actually reduces speed, which means that there is an acceleration from somewhere
What it actually does is gain an acceleration vector opposite that of gravity, so there is a net reduction in acceleration, which means that there is a velocity vector generated opposing the instantaneous falling velocity vector, which means that it gains negative velocity--but it doesn't go to zero, which means there is a force acting upward on the brick, and since any force acting upwards counteracts gravity, the egg won't break.
Is that what he is saying?:D

[beachnut]

If he is using velocity as most of his ilk do, i.e. speed, he wolld be correct. it doesn't gain SPEED. IT actually reduces speed, which means that there is an acceleration from somewhere
What it actually does is gain an acceleration vector opposite that of gravity, so there is a net reduction in acceleration, which means that there is a velocity vector generated opposing the instantaneous falling velocity vector, which means that it gains negative velocity--but it doesn't go to zero, which means there is a force acting upward on the brick, and since any force acting upwards counteracts gravity, the egg won't break.
Is that what he is saying?:D
The brick will speed up and only a slight change in velocity due to running the momentum would be present.

But the brick is going to speed up as it crushes the egg.

In fact on many soils a solid egg, ie golfball will be driven into the ground as the brick accelerates, and pushes the egg into the ground, or is the ground pushing up?

Our expert has already said that negative acceleration is allowed, and could happen. I am not sure what eggs he has, and I guess there is a brick you could use that would slow down as it cracks and egg but not my brick.

[rwguinn]

The brick will speed up and only a slight change in velocity due to running the momentum would be present.

But the brick is going to speed up as it crushes the egg.

In fact on many soils a solid egg, ie golfball will be driven into the ground as the brick accelerates, and pushes the egg into the ground, or is the ground pushing up?

Our expert has already said that negative acceleration is allowed, and could happen. I am not sure what eggs he has, and I guess there is a brick you could use that would slow down as it cracks and egg but not my brick.

AHHH! The MWO Brick of DOOM!
We'll all be killed! :dl:

[jaydeehess]

Ridiculous, the brick will continue to acellerate right through the eg. Its acelleration will be less than 9.8 m/s, that's all. Its acelleration will not reduce to zero.

To my mind the velocity will continue to increase even if the egg slows the acelleration slightly. that reduction of acelleration will be short lived as well as once the integrity of the egg is broken it will offer only miniscule normal force.

This is what happened at the WTC towers. there was an upward force due to the resistance of the building and the downward force of impact and due to the effect of gravity on the mass. the lower portion of the building was neither capable of withstanding that total force in any fashion but even more, that downward force was not being directed immediatly at the strength members of the building, its columns. The floors could hold only a small fraction of the mass of the building thenselves let alone that of 10 or more stories.

[rwguinn]

Ridiculous, the brick will continue to acellerate right through the eg. Its acelleration will be less than 9.8 m/s, that's all. Its acelleration will not reduce to zero.

To my mind the velocity will continue to increase even if the egg slows the acelleration slightly. that reduction of acelleration will be short lived as well as once the integrity of the egg is broken it will offer only miniscule normal force.

This is what happened at the WTC towers. there was an upward force due to the resistance of the building and the downward force of impact and due to the effect of gravity on the mass. the lower portion of the building was neither capable of withstanding that total force in any fashion but even more, that downward force was not being directed immediatly at the strength members of the building, its columns. The floors could hold only a small fraction of the mass of the building thenselves let alone that of 10 or more stories.
You win the cigar (you may chose a bubble-gum cigar, if you wish).
The acceleration will, indeed decrease, by a tiny amount. It does not go to zero, however. This means that the brick is still accelerating! Which also means that the velocity will continue to increase!
Is science not wonderful?

[Horatius]

I really need to go back to school, and remember how to diagram all this.

Clearly, at the moment of impact, there is some decrease in the acceleration. I wonder if we can model it as a spring?

Prior to impact, we have Fbrick, the force of gravity on the brick, Fegg, the force of gravity on the egg. -Fegg is the reaction force from the ground against the egg.

At impact, Fbrick, Fegg and -Fegg would still exist, but we would have a new set of forces, the "spring" action of the egg deforming. Call it Fdef. This is caused by the brick on the egg, so we'd also have -Fdef, from the egg acting on the brick.

So, initially, the net force on the brick would be Fbrick - Fdef. So the acceleration would be lower, but unless the magnitude of Fdef was equal to or greater than Fbrick, it will continue to accelerate.

As the egg deforms, Fdef increases. It starts at zero (the moment of contact), then increases to some maximum. The maximum would be dictated by the breaking point of the egg.

Since the brick has an initial velocity, to survive, the egg must not only be able to resist the weight of the brick, but also apply some additional force to decelerate the brick to zero, before the egg fails. So to stop the brick, the egg's failure point (FdefMax) would have to be some value greater than Fbrick.

Since we know eggs get crushed by bricks (we do know that, right?), clearly FdefMax is less than the above scenario. We need to determine what FdefMax is. If an egg can support the weight of a brick that is gently laid on it, it could be exactly equal to Fbrick, or a bit more.

As shown above, if Fdef is less than Fbrick, it will continue to accelerate, albeit as a lessened rate of acceleration. At some point, as the Fdef approaches and passes Fbrick, the acceleration would drop to zero. As Fdef increases even more, and approaches FdefMax, the brick actually would slow down a bit.

However, at the point of egg failure, Fdef instantaneously drops to zero, and the brick continues on unimpeded.

So the question becomes, how much greater than Fbrick is FdefMax, and how much does the brick slow down as a result of that difference, and (when considered as a complete event, from contact with the egg to contact with the ground), does the brick undergo net positive or net negative acceleration?

I'm betting net positive, but this guy might have some pretty strong eggs.



Unless I missed something.

[Overman]

E = m*c^NWO

[SYLVESTER1592]

You did realize that he won't accept this as a debunking, did you. He will claim hairsplitting, misrepresentation of his idea and return to the Fnet=0 mantra.
Still...worth the effort

[beachnut]

I need about 5 to 10 times faster frames.

http://forums.randi.org/imagehosting/124474642138c351b8.jpg

http://forums.randi.org/imagehosting/124474642135f80e19.jpg

http://forums.randi.org/imagehosting/124474642138bd38a2.jpg

http://forums.randi.org/imagehosting/124474642138c10fe7.jpg

60th of a second the brick was gaining velocity. But in the last frame the brick is on the sand, golf ball buried, then the brick continues at 1/3 speed or so into the sand for the next 1/60 sec., it even bounces and comes to rest in about the same postion here in 7/60 of a second.

The golf ball was buried, the 1/60 of a second is not enough resolution to see if the golf ball and brick were accelerating sometime during the last 1/60 second frame into the sand. Faster frame rate is needed, 600 per second could do it.

What about an egg, not a model of a egg.

[babazaroni]

oops, already stated.

[beachnut]

I've got a feeling that the brick will not change velocity if the Fdef is equal to Massbrick X 9.8M/S.

Mackey will set us straight.
I finished my egg vs brick, the brick accelerated as it crushed the egg. The young physics dolt must eat the sandy egg words he stated as -

Answer from Yandros42 Physics expert --
No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero. The kinetic energy built up by the falling brick will most certainly shatter it. But if you were to take high speed recording of the brick smashing the egg you would find that the brick was not gaining velocity as it smashed the egg.

Oh, but it did gain velocity. Where did he get his physics degree. We need to know if he was on earth. Maybe his eggs are bigger and gravity is no as great.

What did he really mean. And do I have to post the brick crushing the egg or will you believe me the brick accerates thru the egg?

http://forums.randi.org/imagehosting/1244746421f2706ea3.jpg

http://forums.randi.org/imagehosting/1244746421f26c9bbf.jpg

http://forums.randi.org/imagehosting/1244746421f266ee91.jpg

http://forums.randi.org/imagehosting/1244746421f757d146.jpg

With these frames from the famous 60 frame per second back yard what the hell is a retired airforce pilot with a masters degree in Electrical Engineering doing with an egg and a brick film.

I always wanted to do the bowling ball through panes of glass and prove someone else wrong who said it would take like 40 seconds for a bowling ball from 1300 feet to go through 110 panes of glass spaced as floors of the WTC. I get to pick the glass.

Actually there is enough information here to measure that the brick's acceleration is not altered much by the egg. Where did this kid go to school? (yes I need a flat field lens and more frames per second)

BTW, I can see him now after interview, he will be rationalizing why he was not hired.

[Horatius]

The golf ball was buried, the 1/60 of a second is not enough resolution to see if the golf ball and brick were accelerating sometime during the last 1/60 second frame into the sand. Faster frame rate is needed, 600 per second could do it.

What about an egg, not a model of a egg.



Where are the Mythbusters when we need them?

[Horatius]

What did he really mean. And do I have to post the brick crushing the egg or will you believe me the brick accerates thru the egg?



Did you try just gently putting the brick on the egg? If it can't support the weight of the brick under this condition, the whole question is moot, as the FdefMax would be less than Fbrick, and the net force/acceleration would never go below zero.

[Furcifer]

"No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero." -YandrosIQ42


There's no way someone could get an "A" in physics and make this statement. I'd like to see this "net force" equation on paper, I can't imagine how you would even start to show this?

[beachnut]

Did you try just gently putting the brick on the egg? If it can't support the weight of the brick under this condition, the whole question is moot, as the FdefMax would be less than Fbrick, and the net force/acceleration would never go below zero.
You mean the easy way. Let brick accelerate from F=ma=0 and see if gravity and the ground pushing up break young egg?

Do you want me to do another egg during lunch or afternoon nap time?

[Horatius]

Do you want me to do another egg during lunch or afternoon nap time?


Whenever you can fit it into your schedule, as long as it's on my desk by 5pm.




:D


Of course, we have to get you to do it. If I do it, he'll claim I used a heavier brick, or some such thing.....

[beachnut]

Whenever you can fit it into your schedule, as long as it's on my desk by 5pm.




:D


Of course, we have to get you to do it. If I do it, he'll claim I used a heavier brick, or some such thing.....The brick was at rest over the egg, the egg was accelerated into the ground by gravity assisted by brick. I have no idea how the brick crushed the egg since it can not according to whats-his-name accelerate. I have no idea what to call the ability of brick to end up on the earth after it was on top of egg. The egg is slowly cooking in the afternoon sun.

What do you call it when something moves?

http://forums.randi.org/imagehosting/1244746422a7d27a22.jpg
It looks like the brick on top accelerated and then stopped on lower brick and I think the egg was zeroed out by some unknown zero force.

5 to 7 frames, 60/sec, into the brick acceleration, the egg looks elastic. How do you ban people from YouTube comments, and erase them? I think those who erase and ban need to be labeled as such; there needs to be a place where we can see the things banned by the censorNAZIs out there.

[Horatius]

What do you call it when something moves?




I think the term is "debunkeration".

So we see that FdefMax is less than Fbrick. So the net force on the brick will always be directed downwards, and there will always be some net downwards acceleration, even if it is some small amount less than freefall.

Any bets on what he says now? I bet he complains that the egg was on its side, rather than it's end, since it's stronger in that direction.

[qarnos]

I finished my egg vs brick, the brick accelerated as it crushed the egg. The young physics dolt must eat the sandy egg words he stated as -

Hmmm... your brick had a very obvious tilt as it hit the egg. It should have bounced off and slid to the side, no? :D

Seriously, a much easier experiment would be to make a cylinder out of paper, place it end-on on the ground and gently place a heavy brick on it. By Net Force Boy's reasoning, the paper cylinder should be able to resist the brick.

[qarnos]

Any bets on what he says now? I bet he complains that the egg was on its side, rather than it's end, since it's stronger in that direction.

We'll have to wait for the next equinox to try that one. :D

See here (http://www.badastronomy.com/bad/misc/egg_spin.html) if you have no idea what I'm on about.

[Horatius]

Seriously, a much easier experiment would be to make a cylinder out of paper, place it end-on on the ground and gently place a heavy brick on it. By Net Force Boy's reasoning, the paper cylinder should be able to resist the brick.



Actually, paper cylinders are a lot stronger than most people expect, just like the popcans.


We'll have to wait for the next equinox to try that one. :D

See here (http://www.badastronomy.com/bad/misc/egg_spin.html) if you have no idea what I'm on about.



I was thinking of making the same remark, but I figured egg-boy wouldn't get it :)

[qarnos]

Actually, paper cylinders are a lot stronger than most people expect, just like the popcans.

I actually tried it before I posted, and it collapsed. Maybe Australian paper is inferior? :eek:

[Horatius]

I actually tried it before I posted, and it collapsed. Maybe Australian paper is inferior? :eek:



It depends heavily on how you fold/roll it, and the type of paper. I'm pretty sure I could make one that would hold up a brick.

[gumboot]

Wow. He just doesn't know when to stop does he?

How does he not understand that the "Net Force = 0" argument only applies to the object sitting on the ground, not the thing falling on it? What an idiot.

-Gumboot

[qarnos]

It depends heavily on how you fold/roll it, and the type of paper. I'm pretty sure I could make one that would hold up a brick.

True, you probably could. But the mere fact that I can make one that can't invalidates Net Force Boy's theory... as if it needed any more invalidation.

[Horatius]

True, you probably could. But the mere fact that I can make one that can't invalidates Net Force Boy's theory... as if it needed any more invalidation.



Yes, there is that. I guess we're coming at this from different directions. I'd also like to show them that trying to model the WTC with common household items is a fool's game, as the strengths of such materials simply don't scale well.

But it's all good.

[Furcifer]

I found this borwsing the internet on lightandmatter.com, it think it describes the situation perfectly:
"Force is not energy.
There are two main approaches to understanding the motion of objects, one based on force and one on a different concept, called energy. The SI unit of energy is the Joule, but you are probably more familiar with the calorie, used for measuring food's energy, and the kilowatt-hour, the unit the electric company uses for billing you. Physics students' previous familiarity with calories and kilowatt-hours is matched by their universal unfamiliarity with measuring forces in units of Newtons, but the precise operational definitions of the energy concepts are more complex than those of the force concepts, and textbooks, including this one, almost universally place the force description of physics before the energy description. During the long period after the introduction of force and before the careful definition of energy, students are therefore vulnerable to situations in which, without realizing it, they are imputing the properties of energy to phenomena of force.
:)

[Gravy]

On another note, most people don't realize exactly how strong those cans are in compression. If there are no dents or flaws in the sides of the can, they can hold up a heck of a lot of weight. Back in high school, just a few years after they were introduced into our area, I used to impress people by balancing a person on one of these.I have just balanced on a 15-gram Coke can, so I know it can support 7,257 times its own weight in dead load. Therefore the towers should have been able to support at least a 7.26 trillion pound (3.3 trillion kg) dead load, about as much as 605 Great Pyramids of Khufu (Cheops) at Giza. You can't argue against such obvious physical truths.

[T.A.M.]

lol...does that mean it would take the moon crashing atop the WTCs to make them come down...

TAM;)

[Horatius]

I have just balanced on a 15-gram Coke can, so I know it can support 7,257 times its own weight in dead load. Therefore the towers should have been able to support at least a 7.26 trillion pound (3.3 trillion kg) dead load, about as much as 605 Great Pyramids of Khufu (Cheops) at Giza. You can't argue against such obvious physical truths.



Did you video it? If not, it doesn't count!

But yes, that's exactly the ratio I was going to show them. Thanks for ruining it!

:)


ETA: While I'm thinking about it, if the towers could hold 7,257 times their own mass, what percentage of the buildings in NYC would that be? Any ideas on the number of large buildings in the city?

ETA2: for concrete that's 2200 kg/m3, that's a solid block 1000m on a side, and about 1435 m high.

[Horatius]

lol...does that mean it would take the moon crashing atop the WTCs to make them come down...

TAM;)




No no, just an asteroid.


And here I was, thinking about changing my sig!

[Slayhamlet]

lol...does that mean it would take the moon crashing atop the WTCs to make them come down...

TAM;)

Except the moon would actually just drive the WTC towers into the earth like a hammer to a nail...yep.

:boggled:

[beachnut]

Anyone want some quiche. It has some minerals in it.

Anyone know how to get egg yoke out of a camera lens?

[gumboot]

I have just balanced on a 15-gram Coke can, so I know it can support 7,257 times its own weight in dead load. Therefore the towers should have been able to support at least a 7.26 trillion pound (3.3 trillion kg) dead load, about as much as 605 Great Pyramids of Khufu (Cheops) at Giza. You can't argue against such obvious physical truths.


Alternatively it's about the same mass as the entire world's oil produced in 2001, and ten times the mass of the entire human race.

I know that office high rise occupancy rates have been increasing, but that's ridiculous.

-Gumboot

[Myriad]

I thought it might be amusing to mark up your egg-and-brick photographs with callouts showing "pods" on the bricks, asking "what's this mysterious shadow"? and pointing out all the "squibs."

Then I thought, it might be nearly as amusing, and much less work, to just write about doing this.

I'm probably wrong.

Except the part about it being much less work. I'm right about that.

Respectfully,
Myriad

[beachnut]

I thought it might be amusing to mark up your egg-and-brick photographs with callouts showing "pods" on the bricks, asking "what's this mysterious shadow"? and pointing out all the "squibs."

Then I thought, it might be nearly as amusing, and much less work, to just write about doing this.

I'm probably wrong.

Except the part about it being much less work. I'm right about that.

Respectfully,
Myriad
Egg was ejected much further than a gravity collapse could do. In fact never in the history of eggs has a red brick crushed an egg and ejected the yoke. It was a squib that pushed out the yoke with an explosive force. Some planted thermite/thermate/RDX explosives in my sand pile. I hate to tell you want the cats did to the sand pile, it is starting to smell like LCFC here in the sunny foothills of the Sierra Nevada Mountains.

[jhunter1163]

I have just balanced on a 15-gram Coke can, so I know it can support 7,257 times its own weight in dead load. Therefore the towers should have been able to support at least a 7.26 trillion pound (3.3 trillion kg) dead load, about as much as 605 Great Pyramids of Khufu (Cheops) at Giza. You can't argue against such obvious physical truths.

So, from this, we can deduce that Gravy weighs 108.85 kg. He's a big fella all right.

[qarnos]

So, from this, we can deduce that Gravy weighs 108.85 kg. He's a big fella all right.

I was more surprised to see an American express weight in grams! :D

[gumboot]

I've got a question...

Net Force apparently (and mysteriously) always equals zero. As we know, normal force (the thing that stops you sinking into the ground) isn't just "the ground pushing up", it's actually any surface "pushing back". When he place your hand on a wall, for example, normal force prevents your hand going straight through it.

How would this idiot's "net force equals zero" assertion play out in a lateral collision, in which the moving object was no longer under the influence of any force moving it forward?

For example, let's take a bullet. When it impacts something, that impacted surface exerts a normal force on the bullet, just as the ground exerts a normal force on the WTC, and just as the lower section of the WTC exerts a normal force on the upper section.

Now, assuming his theory that in all collision net force always equals zero... how would that play out with a bullet hitting
A) An easily penetrated surface
B) A difficult to penetrate surface
C) An impenetrable (bullet proof) surface
Meanwhile, perhaps physics boy can explain what's happening in the last example on the video below (starting about the 6:17 mark)

zMZMIOVmj1g

-Gumboot

[Myriad]

I have just balanced on a 15-gram Coke can, so I know it can support 7,257 times its own weight in dead load. Therefore the towers should have been able to support at least a 7.26 trillion pound (3.3 trillion kg) dead load, about as much as 605 Great Pyramids of Khufu (Cheops) at Giza. You can't argue against such obvious physical truths.

You're trying to tell me that a skyscraper is as flimsy as a thin aluminum Coke can? Ha ha ha ha ha ha ha.

Dude, don't you know STRUCTURAL STEEL IS STRONGER THAN THIN ALUMINUM!!!! it would hold much more weight than that! I don't need any calculations to show this, it's obvious. But if you need proof, here's a link to a chart containing very large numbers. (http://library.thinkquest.org/5427/maze.gif)

And if soda cans are so strong then why were none found in the debris? Last time I was on a plane they had whole carts full of little cans of soda. No soda cans = no planes at ground zero!! Look at the bottom of the can, you'll see it's curved. That's to resist the force of the ground as it pushes up on the can, allowing the can to be crushed for dispoal or recycling. Did the World Trade Center have curved bottoms? I DON'T THINK SO!!! So how could they collapase? Here's a clue: Travis Fergusen R.Gr. of the N.I.P.A. says there were 99 BOTTLES OF BEER ON THE WALL in the North Tower. Where are those bottles now? Did they really "just happen" to fall? Don't we have the right to answers to these questions? Let me remind you that NO BUILDING IN HISTORY has ever been filled with carbonated beverage, had its top popped open and its contents sucked out through a plastic straw! It's just not possible!

Carbonation, carbon dioxide, global warming, warm beer, beer bottles, soda cans, straws, straw men, straw hats, politicians, political parties, keg parties, single-serving containers, self-serving conspirators, cover-ups, covert ops, overt cops, pop tops, IHOP, MIHOP -- are you beginning to see the pattern here? Building Seven was pulled, cans of Seven-Up have pull tabs, and the tab was about seven million dollars. Or will you try to pretend it's not obvious? You can STAND on a CAN, but CAN you STAND the truth?

Respectfully,
Several beers, using Myriad as a shill

[jaydeehess]

Eggs are problematic in that one cannot get them to stand well on a flat surface and paper cylinders are also difficult to work with.

my suggestion would be shoeboxes.For this one needs a couple dozen identical boxes.

First, place a brick on top of the shoebox, use smallish bricks btw, and it would be good to have a brick the same width and length as the box, and ensure that the box can support the mass of that brick. Now place a 1/8" iron plate with the same width and length as the brick, onto the brick. Continue doing this until the box just shows that it is breaking down, that is, when a side or corner kinks. At this value the box has failed yet still managed to halt the collapse.

Now, new boxes again. Lift an unplated brick up 1 cm and drop it flat on the box. Continue (using a new box each time) redoing this until you reach a height at which the box crushes to the same amount as above. At this point the falling lone brick is imparting the same amount of force on the box as the brick-plus-plates mass was.

Once again go back to the unplated brick and drop it again from increasing heights until you reach the point at which the box completely crushes to the ground. Obviously at this point the brick has imparted more force upon the box than it did when the box just failed but managed to stop the collapse. However it is just possible that the forces did balance and that the brick reached a terminal velocity through the box.(which is what his,"it would crush at a constant velocity" means)

Now, if you again raise the brick even higher you obviously increase the force imparted on the box yet again. If in the last paragraph's actions you had arrived at the point at which the forces balanced and the brick reached a terminal velocity then.
NOW, by raising the brick still further you ensure that the force imparted on the box is greater than the force the box will be able to balance out and THUS the brick will experience continuing acelleration until it reaches ground level!

Q(rule8)ED

,,,, eta,,,,
and the beauty of such an experiment is that it uses no math at all just an understanding of physics and it uses nothing other than the forces involved rather than momentum and energy as well. It is comparitive and intuitive and should be easily digested by a CT.
It also models what would have been the case if the upper section had fallen onto the load bearing structural members(the columns) in the WTC towers, a considerably more robust resistance than if the uppper section did not do that.

right?

What physics boy wunder missed is that the falling mass can impart more force than the structure can withstand.

[Horatius]

You're trying to tell me that a skyscraper is as flimsy as a thin aluminum Coke can? Ha ha ha ha ha ha ha.

Dude, don't you know STRUCTURAL STEEL IS STRONGER THAN THIN ALUMINUM!!!! it would hold much more weight than that! I don't need any calculations to show this, it's obvious. But if you need proof, here's a link to a chart containing very large numbers. (http://library.thinkquest.org/5427/maze.gif)

And if soda cans are so strong then why were none found in the debris? Last time I was on a plane they had whole carts full of little cans of soda. No soda cans = no planes at ground zero!! Look at the bottom of the can, you'll see it's curved. That's to resist the force of the ground as it pushes up on the can, allowing the can to be crushed for dispoal or recycling. Did the World Trade Center have curved bottoms? I DON'T THINK SO!!! So how could they collapase? Here's a clue: Travis Fergusen R.Gr. of the N.I.P.A. says there were 99 BOTTLES OF BEER ON THE WALL in the North Tower. Where are those bottles now? Did they really "just happen" to fall? Don't we have the right to answers to these questions? Let me remind you that NO BUILDING IN HISTORY has ever been filled with carbonated beverage, had its top popped open and its contents sucked out through a plastic straw! It's just not possible!

Carbonation, carbon dioxide, global warming, warm beer, beer bottles, soda cans, straws, straw men, straw hats, politicians, political parties, keg parties, single-serving containers, self-serving conspirators, cover-ups, covert ops, overt cops, pop tops, IHOP, MIHOP -- are you beginning to see the pattern here? Building Seven was pulled, cans of Seven-Up have pull tabs, and the tab was about seven million dollars. Or will you try to pretend it's not obvious? You can STAND on a CAN, but CAN you STAND the truth?

Respectfully,
Several beers, using Myriad as a shill



Nominated! (http://forums.randi.org/showthread.php?postid=2589590#post2589590)

[westprog]

"No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero." -YandrosIQ42


There's no way someone could get an "A" in physics and make this statement.

Course work.

[westprog]

I am refering to the usual claim that to have occur what we witnessed (violent expulsion of debris during the collapse) there would have to have been explosives on every floor.

He's making so many confused and contradictory statements compressed into such a small space that we can't help stepping on each other as we pick them apart.

[SYLVESTER1592]

”Well if the net force is zero and an object collides with another object of equal density the collision dynamics are dependent on the structure of the objects and the kinetic energy of each object. Incase you failed to understand the entire point it is this: the collapse wave should not accelerate once it enters the structurally sound area.” -Yandros42

He has finally almost completely backtracked.
Well, he’s slowly getting there. Remaining errors :

1. He doesn’t yet understand the difference between elastic and inelastic collision and the relevance of the conservation of momentum in collisions.
2. He still does not realize the structurally sound area resisting the impact is one floor thick with acceleration between the floors.
3. He may now finally start to realize Fnet=0 only means no acceleration, but not necessarily no movement. No movement won’t be achieved until the structure hits the ground. But he already refused that fact, because Fnet=0 on impact in his mind and by his reasoning (to him) this means a collapse of the floors is impossible.
4. He simplified his model to blocks with an uniform resistance, but did not describe or consider the limits of his model.
5. He is convinced the only explanation is demolition, without any necessary evidence to support this conviction.

In his mind one floor can withstand the impact of 14 or 24 floors over 3.7m, because they were part of the lower block.
This means:
m=29/110*510.000.000kg=1.345 E8 kg
Since he doesn’t think the conservation of momentum applies (?!),
:eye-poppi
we’ll do it his way:

S(t)=1/2*9.8*t^2=3.7m
t=0.87s
v=a*t=8.52m/s (still close to Greening)
KE top=1/2*1.345 E8 kg *8.52^2=4,88 E9 J

This is still a lot (7.77 times) more then the capacity of one floor (6,28 E8 J)

According to Y. and Judy Woods' "fiziks" the collapse must stop completely (=no transfer of momentum, no conservation of momentum), break under the collapsing weight and fall again to the next floor again reaching an acceleration of 8.52m/s in 0.87s. (or else F. Greening is right and the floors must speed up)
When you do this according to Yandros42's presentation, the total time for collapse would be 1 minute and 36 seconds = completely wrong, in J. Woods' theory also the top floors would have to collapse separately and it would take even longer

When you take into account the loss of energy for every collapse and use Judy Woods fiziks: Every floor will absorb some of the energy of the collapse (the “common sense”argument). This would work out to:
4.88 E9J- 6.28 E8J + ½(29+N/110*510000000)*v^2- 6.28 E8J+…=9.07 E11 J (a little off but close to the potential energy of the towers). Nevertheless they don’t see a reason for any crushing or pulverization of the building.

I think, he fails to realize that the floors don’t carry the weight of the building, but mostly their own weight and therefore the velocity, at no moment in time, will reach zero (except on reaching the ground). Most importantly he ignores that in a collapse the conservation of momentum applies (one of the basic rules in collisions) . The reduction of the total downward acceleration is only marginally affected by the resistance of the floors and will still result in a collapse CLOSE to free fall when considering the conservation of momentum, as described by F. Greening.

In conclusion: the argument that the observations leave no other explanation then demolition is therefore based on an incomplete and flawed interpretation of the events and unfounded suggestive association with apparently similar events, and is in doing so completely wrong.

[Mancman]

Yandros' most recent parade of idiocy:
sBfkAzWbnvM

"That stupid JREF forum, you're all backpatters, you make me sick, you're aruging disinformation."

[SYLVESTER1592]

”fall again to the next floor again reaching an acceleration of 8.52m/s in 0.87s.


Sorry, I mean a velocity of course.

[Slayhamlet]

This kid is the intellectual equivalent of a sack of hammers.

[Slayhamlet]

Sorry, I mean a velocity of course.

You can edit your post.

-nevermind, I see you did.

[jaydeehess]

Yandros' most recent parade of idiocy:
sBfkAzWbnvM

"That stupid JREF forum, you're all backpatters, you make me sick, you're aruging disinformation."

Now that there is funny!


i don't suppose he has even read the posts that directly take on his misinformed physics. We are just wrong and taking our cues from some God of the NWO.

[qarnos]

Yandros' most recent parade of idiocy:
sBfkAzWbnvM

"That stupid JREF forum, you're all backpatters, you make me sick, you're aruging disinformation."

"The physics are obvious, the truth is self-apparent".

Yet every physicist in the world disagrees with him. Are they all shills? :confused:

[gumboot]

”Well if the net force is zero and an object collides with another object of equal density the collision dynamics are dependent on the structure of the objects and the kinetic energy of each object. Incase you failed to understand the entire point it is this: the collapse wave should not accelerate once it enters the structurally sound area.” -Yandros42

He has finally almost completely backtracked.
Well, he’s slowly getting there. Remaining errors :

1. He doesn’t yet understand the difference between elastic and inelastic collision and the relevance of the conservation of momentum in collisions.
2. He still does not realize the structurally sound area resisting the impact is one floor thick with acceleration between the floors.
3. He may now finally start to realize Fnet=0 only means no acceleration, but not necessarily no movement. No movement won’t be achieved until the structure hits the ground. But he already refused that fact, because Fnet=0 on impact in his mind and by his reasoning (to him) this means a collapse of the floors is impossible.
4. He simplified his model to blocks with an uniform resistance, but did not describe or consider the limits of his model.
5. He is convinced the only explanation is demolition, without any necessary evidence to support this conviction.

In his mind one floor can withstand the impact of 14 or 24 floors over 3.7m, because they were part of the lower block.
This means:
m=29/110*510.000.000kg=1.345 E8 kg
Since he doesn’t think the conservation of momentum applies (?!),
:eye-poppi
we’ll do it his way:

S(t)=1/2*9.8*t^2=3.7m
t=0.87s
v=a*t=8.52m/s (still close to Greening)
KE top=1/2*1.345 E8 kg *8.52^2=4,88 E9 J

This is still a lot (7.77 times) more then the capacity of one floor (6,28 E8 J)

According to Y. and Judy Woods' "fiziks" the collapse must stop completely (=no transfer of momentum, no conservation of momentum), break under the collapsing weight and fall again to the next floor again reaching an acceleration of 8.52m/s in 0.87s. (or else F. Greening is right and the floors must speed up)
When you do this according to Yandros42's presentation, the total time for collapse would be 1 minute and 36 seconds = completely wrong, in J. Woods' theory also the top floors would have to collapse separately and it would take even longer

When you take into account the loss of energy for every collapse and use Judy Woods fiziks: Every floor will absorb some of the energy of the collapse (the “common sense”argument). This would work out to:
4.88 E9J- 6.28 E8J + ½(29+N/110*510000000)*v^2- 6.28 E8J+…=9.07 E11 J (a little off but close to the potential energy of the towers). Nevertheless they don’t see a reason for any crushing or pulverization of the building.

I think, he fails to realize that the floors don’t carry the weight of the building, but mostly their own weight and therefore the velocity, at no moment in time, will reach zero (except on reaching the ground). Most importantly he ignores that in a collapse the conservation of momentum applies (one of the basic rules in collisions) . The reduction of the total downward acceleration is only marginally affected by the resistance of the floors and will still result in a collapse CLOSE to free fall when considering the conservation of momentum, as described by F. Greening.

In conclusion: the argument that the observations leave no other explanation then demolition is therefore based on an incomplete and flawed interpretation of the events and unfounded suggestive association with apparently similar events, and is in doing so completely wrong.


Don't forget the initial failure resulted in a fall of more than one floor, as the entire aircraft impact area failed at once.

For WTC1 the fall was 18m, for WTC2 it was 26m. The impact energies were 9.7GJ (WTC1) and 30.3GJ (WTC2), spread over a maximum footprint of 45m2.

-Gumboot

[SYLVESTER1592]

I still need to check the calculations for several floors, but decided to use the minimal collapse of one floor to demonstrate the amount of energy involved and avoid any doubt about the possibility of the collapse, since this is really the mean issue for Yandros. The values used favour Yandros' point of view and still prove him wrong. Ofcourse a more precise estamation would contradict Yandros even more.

[Furcifer]

I see now Yandros has proven gravity at ground zero was greater than anywhere else on terra firma. This localized gravitational instability should be investigated further. I'm proposing we form a tack force of our "best scientists working in this field today" Dr. Judy Wood, a.k.a. "Sleeping Beauty" and Yandros42, a.k.a. "NetFroce=zero". Funding will of course be provided by SonofNewo, a.k.a "Diet Coke Can Model", assuming he get all the glue off the cans and gets his full deposit back.
If i couldn't laugh, I'd cry.

[SYLVESTER1592]

*Signs of the pseudo-genius*

While lying in their hammock amidst the gardens trees, they look at the apples falling from the tree...And wonder: How does the hammock hold up the tree?

[jaydeehess]

How's this look guys?

http://forums.randi.org/imagehosting/129594644abf43eace.bmp

F1 is the maximum strength of the lower structure. This represents the maximum force that structure can resist while the structure remains intact. Of course this number goes down when the structure is in any way damaged but lets assume it remains constant.

F2 is the force due to gravity that the falling mass exerts. this is equal to M times g

F3 is the force of impact. It can be calculated a couple of ways. It is the change in momentum divided by the time of contact or it is the energy of the falling mass divided by the distance it travels during which the energy is transferred to the other object.

Obviously in any building F1>F2 Buildings are designed that way, its a safety margin

If F2 + F3 = F3 then the mass will reach terminal velocity and continue to the ground

If F2 + F3 > F1 then the mass will continue through the lower structure , acellerating all the way to the ground.

Only if F2 + F3 < F1 will the collapse come to a halt

[SYLVESTER1592]

How's this look guys?



:eek:

Are you now not making the same mistake as Yandros? Asuming a homogenous lower and upper structure? Next argument will be thermodynamics.
:covereyes
Please, NO...don't, No Yandrification of this problem.

If you are using this to represent one floor, OK
Agree? :)

[Horatius]

How's this look guys?

http://forums.randi.org/imagehosting/129594644abf43eace.bmp






There's not enough Zeros! Obviously not Scientific enough!



:D

[Minadin]

How's this look guys?

http://forums.randi.org/imagehosting/129594644abf43eace.bmp

F1 is the maximum strength of the lower structure. This represents the maximum force that structure can resist while the structure remains intact. Of course this number goes down when the structure is in any way damaged but lets assume it remains constant.

F2 is the force due to gravity that the falling mass exerts. this is equal to M times g

F3 is the force of impact. It can be calculated a couple of ways. It is the change in momentum divided by the time of contact or it is the energy of the falling mass divided by the distance it travels during which the energy is transferred to the other object.

Obviously in any building F1>F2 Buildings are designed that way, its a safety margin

If F2 + F3 = F3 then the mass will reach terminal velocity and continue to the ground

If F2 + F3 > F1 then the mass will continue through the lower structure , acellerating all the way to the ground.

Only if F2 + F3 < F1 will the collapse come to a halt

I think you meant that: "If F2 + F3 = F1 then the mass will reach . . ."

[beachnut]

You guys took the ridiculous egg analogy out of context and put the egg on sand. Is sand really the same as bedrock? You morons. This is all in the context of the world trade centers and some assumptions are made. Assumptions like the towers are firmly rooted into the bedrock. There's a reason they don't build buildings on sand.

You JREF people are just ridiculous. You'll twist anything and everything and take it all out of context. But in reality you are only kidding yourselves
Yowserrsserrs, you are wrong about that too. The egg was put on bed rock. The brick went from zero to faster, to bedrock stop. Please tell me why my bedrock model is not good enough for brick, egg, or even moose and squirrel. Where did yandros42 get his degree from? We need to remove accreditation now!


http://forums.randi.org/imagehosting/1244746422a7d27a22.jpg

As you see here the bedrock modeled as a brick pushes up, egg was pushed down, top brick was acted on by the gravity thing and the egg shell failed. Which part of F=0 did I mess up?

Actually our yandros41+0+1 may not understand energy and the real world. Maybe on paper F=0 works on the flat world of paper an pen.

Why does yandros42 ban everyone who loves his F=0 physics? Is the y-man really the physicsNAZI? NO FORCE = 0 FOR YOU!

As show here, when the lower support of the WTC, the fire weakened steel modeled as an egg, could no longer hold up the top of the WTC. Also we can model the initial fall as hitting the egg, the lower section and see as the lower section fails the upper section accelerates until it hits the ground.

[beachnut]

The momentum is what? You mean the momentum of the top falling on the bottom can not destroy the next floor? This is not yandros but a fellow honors physics expert.
"No the momentum is transferred into the ground" so you think if someone hit you in the head with a sledge hammer your feet will explode? I suggest you try this and let us know what happens. I've got $10 that says your head cracks before your feet. look up "inertia"

Did anyone see the base of the WTC explode when the top fell on the first section below? Is this a good question?

I will not want to see a head and feet if the sledge hammer if falling from 10 or 20 feet, and from 1300 feet I do not want to be within 600 feet, maybe 2500 feet when this demo takes place. A sledge hammer from 1300 feet just may explode your feet very shortly after passing through the head for towards the earth core. Where did we learn the momentum was all sucked up by the earth.

Yandros42 said -
The momentum of the initial collision between the falling mass and the undamaged structure is transferred into the earth. The force of the collision is clearly not great enough to damage the central support columns to a point where their structural resistance becomes null. This is apparent in the lack of buckling observed and the way the towers crumble rather than falling as a single mass. Please review my 4th video (debunking the debunkers) for a graphical explanation of this point.
Darn, he has debunked all with the earth eats up momentum and F=0. Debunked.

Is Yandros42 really Yandrewbob Wood, son of Judy Wood?


Yandros42 (http://www.youtube.com/user/Yandros42) (2 days ago)
No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero. The kinetic energy built up by the falling brick will most certainly shatter it. But if you were to take high speed recording of the brick smashing the egg you would find that the brick was not gaining velocity as it smashed the egg.
He is from down-under, down-under F=0 is correct those guys are upside down, even toilets flush the other way.

[chillzero]

Why do these things kept being drawn as if there was a big gap, and the top just hovering over the bottom? Did I miss some levitation event that day?

[beachnut]

Yandros42 (http://www.youtube.com/user/Yandros42) (46 minutes ago)
Yeah it amazes me. This is what mainstream science has come to because of egotistical fools. Although mainstream science and mainstream medicine were never really any good. Most of the modern world owes itself to the hard work of individuals shunned, attacked and degraded by people exactly like this. Most notably Einstein, Tesla, and Pasteur (the guy who more or less discovered bacteria is what makes us sick when we eat spoiled food.)

Yandros42 is now comparing himself to Einstein, Tesla, and Pasteur.

Yandros42 is more like Hitler and Dr. Goebbels spewing propaganda and lies about 9/11 and F=0ing up physics beyond recognition. Yandros42, by banning all comments, you are like a NAZI. Soon someone will post your junk where you can not ban real people from making intelligent posts about how dumb your physics lessons are. I am going to use your study in my class, and use you egg/F=0 for a lab where we calculate acceleration with high speed video, and use your banning as a lesson on propaganda and how NAZIs shaped opinion.

Someone can use you are an example of bad physics, example of censorship and propaganda. Plus more. You are a perfect example of a self appointed expert dolt. You are going to be real upset when your physics teacher points out you mistakes. Hope she is not Judy Wood.


Yandros42 (http://www.youtube.com/user/Yandros42) (3 hours ago) marked as spam
On that note I'll happily ban/block all and any JREF people posting here. Because frankly I am sick of your rule8. If you want to argue the real physics go ahead. But all you do is setup strawmen arguments and take what I say out of context. You are a joke. You think this is what real science, real physics is about? No. It is a very simple force equation and half of you are too stupid to realize that. The other half have such bad psychological denial they can't accept anything as fact.
I used physics and energy to prove the WTC could fall and the collapse would only be 10 percent slower than free fall from the top of the WTC. Just to prove to myself. I was wondering what the speed should be since I found a few really dumb people saying stupid things and they called themselves, "truth". I found out they were making up stuff and telling lies, not even close to the truth. In the real world only some sections of the WTC hit the ground at 10 seconds or less. Most of the building hit the ground or came to rest much later, if up to 30 seconds is much later.

[jaydeehess]

I think you meant that: "If F2 + F3 = F1 then the mass will reach . . ."

(rule 8)!

yes.

[Horatius]

It is a very simple force equation and half of you are too stupid to realize that.


And there we have his fundamental flaw.

Let me put this in a way he might understand. Everyone else, just ignore this next line:

It is NOT a very simple force equation and he is too stupid to realize that.

Equations such as he uses are nice, but they simply are not up to calculating such complex, real-world situations. The huge number of interactions in something like a building, let alone a building that is collapsing, simply can't be understood in terms of a "simple force equation".

Until he realizes that (and he never will) he'll just keep repeating his "Net Force is Zero" mantra, and his echo-chamber friends will keep reinforcing his beliefs.

[jaydeehess]

:eek:

Are you now not making the same mistake as Yandros? Asuming a homogenous lower and upper structure? Next argument will be thermodynamics.
:covereyes
Please, NO...don't, No Yandrification of this problem.

If you are using this to represent one floor, OK
Agree? :)


Keeping Is Simple for yandeoS
I did mention that F1 would become smaller once the lower structure was damaged.

Where in God's name does he get that the momentum is all transferred to the Earth? The upper section contains a certain amount of momentum. It loses that momentum as its kinetic energy is transferred to the lower structure. This transfer of energy takes place over time and distance travelled and as it occurs it is marked by a reduction in velocity which by definition means that the momentum of the moving mass gets smaller.(only if the forces acting downward are less than those acting upward. If downward forces are greater then the velocity of the falling mass increases and so does the momentum of that falling mass)

ONLY if the lower structure was of the same strength as the bedrock would yandross be able to claim that the momentum was all transferred directly to the bedrock. He is ignoring centuries of structural engineering. The structure has a failure point. If enough force is applied that is greater than the force the structure can resist then the structure begins succumbing to that force, IT MOVES, it bends, it fractures. No office building is a solid structure, they are made of floors held up by their attachments to load bearing columns. If anything buggers up those columns then they will not efficiently transfer that load to the ground. Only load on those columns will be transfered to the ground.

In the case of the towers first of all something did bugger up the columns at the impact/fire floors. The ability to resist the dead load was reduced throughout the time the buildings were on fire , at the fire floors. As a result the columns started to bend uder the load as they did so the load was taken up by other columns, other columns continued to weaken as the fire moved through the building. Some columns, having already foreshortened under heat and load would then cool BUT they would no longer be straight and if not straight they could not possibly regain their ability to carry more load. Eventually a point was reached when there was no more reserve capacity in the columns and any additional load tranfers resulted in rapid failure of the columns(they bent and/or fractured).

The upper portion of the building then fell through the first floor height BECAUSE the columns no longer lined up where they had bent and/or fractured.

The impact forces and the gravity forces due to the mass of the falling upper section then could only be transferred to the columns as it was imparted upon the floor space and transfered via the truss system to the columns. The truss seats were never designed to be able to carry the force of the entire building above them let alone that plus the impact forces. Thus the vast bulk of downward forces were not on the columns and thus very little of that downward force was taken by the columns.

As this happened the floors were ripped away, the columns of the lower section lost lateral support and at the same time were being buffeted by the falling debris and they also buckled, bent and/or fractured.

The acelleration of the collapse was about 10-15% less than gravity meaning that the resistive force offered by the lower structure was 10-15% of the total force of the falling debris The lower section only offered the resistance it did because the force was not being taken on by the strength members, the columns, of the structure. Those columns in turn relied upon the trusses of the floors for lateral support. The columns of the intact building held the mass of the entire building BUT once they lose lateral support they could not remain standing (look up Euler and critical load), would not have been able to even stand on their own let alone while being buffeted by large dense moving debris.

As columns bent during collapse they would be transfering some of that energy as heavy lateral vibration , at the speed of sound, down their length. This may well have been large enough to snap some truss connections well ahead of the collapse zone itself and certainly would result in the sound reaching the ground by two paths, that through the columns and that through the air. In this way you have witnesses saying they heard booms ahead of the collapse coming from the basement. The sound coming via the columns would be travelling much faster than that through the air. It also explains why things were falling from the ceilings of the ground floor while the towers collapsed. It was also happening on other floors but no one there lived to tell of it and only a couple on the ground floor did.


Better Sylvester?:D

[SYLVESTER1592]

Keeping Is Simple for yandeoS
... Better Sylvester?:D

YES :D Thank you :)

[Furcifer]

And there we have his fundamental flaw.
It is NOT a very simple force equation and he is too stupid to realize that.



I hate to be a stickler for detail, but this IS a simple force equation. The building's mass remains the same for the entire collapse (plane mass not withstanding), and the acceleration due to gravity remains the same.

The "force" on the building remains the same from when it it was standing to when the whole friggin thing was lying on the ground in little tiny pieces F=ma!
That being said, It is a simple kinetic energy equation and therefore:

It is NOT a very simple force equation and he is too stupid to realize that.

He does not know the difference between energy and force.
And beachnut: I proposed the question of his feet exploding if he got hit in the head because he claimed that the upper masses kinetic energy would be transmitted down to the ground and the base would have been deformed before the upper floors. How he gets that is beyond me.
And finally, I must confess that I was the one who spawned this god awful demon, his first video was a response to a comment I made on a video over at YouTube. I tried to teach the kid a little bit of physics and he went insane. May god have mercy on my soul.

[slyjoe]

Well, at least we know who to blame. My dog forgives you. :)

I think you touched on a fundamental problem with CTers - not knowing differences between force, energy and momentum. Or gravity. Or logic. Or...never mind.

[SYLVESTER1592]

I hate to be a stickler for detail, but this IS a simple force equation. The building's mass remains the same for the entire collapse (plane mass not withstanding), and the acceleration due to gravity remains the same.

The force on the building remains the same...Uhm didn't a big chunk of the mass get expelled...? I think mostly concrete dust. I think 40% of the building was concrete according to Greening, (even more mass was expelled according to Ross, but still no where near to the 80-90% he is looking for). I don´t want to be a stickler, but...well if we´re on the subject... :p No matter, I know what you are trying to say :) And agree...

[beachnut]

I hate to be a stickler for detail, but this IS a simple force equation. The building's mass remains the same for the entire collapse (plane mass not withstanding), and the acceleration due to gravity remains the same.

The "force" on the building remains the same from when it it was standing to when the whole friggin thing was lying on the ground in little tiny pieces F=ma!
That being said, It is a simple kinetic energy equation and therefore:

It is NOT a very simple force equation and he is too stupid to realize that.

He does not know the difference between energy and force.
And beachnut: I proposed the question of his feet exploding if he got hit in the head because he claimed that the upper masses kinetic energy would be transmitted down to the ground and the base would have been deformed before the upper floors. How he gets that is beyond me.
And finally, I must confess that I was the one who spawned this god awful demon, his first video was a response to a comment I made on a video over at YouTube. I tried to teach the kid a little bit of physics and he went insane. May god have mercy on my soul.
My feet are exploding.

But boy wonder continues teaching physics to the masses.

Yandros42 (http://www.youtube.com/user/Yandros42) (15 hours ago)
You mean like:
s = ut + 1/2at^2
v^2 = u^2 + 2as
v = u + at

Sure I know them. Look you can even use the first one there to prove that the collapse encountered no resistance:

We know from seismic data that one of the towers fell in 8.4 seconds. We know the towers were 410 meters high. We know that the planes came in at about 350 meters up.

350 = 0 + 1/2 * a * 8.4^2
350 / (8.4^2 * 0.5) = a
a = 9.92063492 m/s/s (I.e. gravity plus or minus the margin of error.)

How can he use seismic data to show how fast the WTC fell? What energy level would be on the seismic data from the impact zone for the first second of WTC movement? You have to know the capabilities, threshold, and resolution of the seismic data before you can say what it means for a building falling. Did the seismic data have the final core falling after 25 seconds? That is the part of the core that the cutter charges must of failed on. And not sure how those guys lived through all the cutter charges in the core where they were rescued from.

If Yandros42 was not a censorNAZI, I could ask him.

Good job setting off boy wonder, when he figures out the brick continues to accelerate when it hits an egg he will have to pack up his videos and hide. I am saving them to show to his class if he becomes a teacher. Yandros will be able to teach his students to be skeptics of teachers using himself as the example.

Please poke him again, I love his videos. We need a debunk the debunkers final chapter. I love physix movies.

[Furcifer]

The force on the building remains the same...Uhm didn't a big chunk of the mass get expelled...? I think mostly concrete dust. I think 40% of the building was concrete according to Greening, (even more mass was expelled according to Ross, but still no where near to the 80-90% he is looking for). I don´t want to be a stickler, but...well if we´re on the subject... :p No matter, I know what you are trying to say :) And agree...

ah sylvester, my good friend, why are you giving him more ammo? :) no the expelled mass was still part of the original building. in fact the force acting on the building to this day is still the same! less any mass that may have escaped the the earth's gravitational field, has been used in a chemical process or beta decayed. :) but i know YOU know what i am trying to say. did you get that job?

[SYLVESTER1592]

ah sylvester, my good friend, why are you giving him more ammo? :) no the expelled mass was still part of the original building. in fact the force acting on the building to this day is still the same! less any mass that may have escaped the the earth's gravitational field, has been used in a chemical process or beta decayed. :) but i know YOU know what i am trying to say. did you get that job?

Relax :D I'm not providing him with ammo... I'm actually defending your case. The reports that some of the mass did not exert a permanent force on the lower part of the building during a collapse are not going to change the outcome even in a worst case scenario, they only complicate the calculations of a collapse... It's marginal, insignificant, but truthers cling to it so be prepared.

[Furcifer]

hehe, i know sylvester. did you get the job?

[SYLVESTER1592]

hehe, i know sylvester. did you get the job?

Not yet :D Are you offering it? ;) Wouldn't dream to be so pretentious as to assume I could correct or teach you. But thank you anyway :D

[Cl1mh4224rd]

Yandros42 is now comparing himself to Einstein, Tesla, and Pasteur.

I believe that earns him 40 points (http://math.ucr.edu/home/baez/crackpot.html)... :)

[Horatius]

I hate to be a stickler for detail, but this IS a simple force equation. The building's mass remains the same for the entire collapse (plane mass not withstanding), and the acceleration due to gravity remains the same.





That's the downward force due to gravity. I agree it remains pretty much constant. The problem is, for him to assert that net force is zero, he has to be assuming the lower section exerts an upward force on the upper part that exactly matches the force of gravity on the upper part. That was true when the building was whole, but after the collpase began it was no longer true, as the collapsing structure simply could not transfer an equal load to the ground.

Once you're into the collapse, modeling the interactions of all the parts, and trying to sum to a simple Ftotal that you can apply to the entire mass of the building is a fools game. And that's essentially what he's trying to do - he's modeling a huge, complex, interdependent structure as essentially perfectly rigid point masses, and then acting like that is the last word on the physics involved.

[rwguinn]

That's the downward force due to gravity. I agree it remains pretty much constant. The problem is, for him to assert that net force is zero, he has to be assuming the lower section exerts an upward force on the upper part that exactly matches the force of gravity on the upper part. That was true when the building was whole, but after the collpase began it was no longer true, as the collapsing structure simply could not transfer an equal load to the ground.

Once you're into the collapse, modeling the interactions of all the parts, and trying to sum to a simple Ftotal that you can apply to the entire mass of the building is a fools game. And that's essentially what he's trying to do - he's modeling a huge, complex, interdependent structure as essentially perfectly rigid point masses, and then acting like that is the last word on the physics involved.

Dynamics: Sum(F(t))=m*a
Statics: a=0.0
Dynamic: moving; changing.
Static: unchanging, not moving.

Amazing how that works out. Too bad those testosterone-saturated brains (or some psyche-changing drug) can't tell the difference between moving and non-moving. It really isn't that difficult if you have any attachment to reality...

and don't nobody get pedantic on me here. for all practical purposes, and for ease of solution, the equation takes into account "g", as in Sum(F(t))=m*g+K*x+B*v+Fext(t)

[Furcifer]

That's the downward force due to gravity. I agree it remains pretty much constant. The problem is, for him to assert that net force is zero, he has to be assuming the lower section exerts an upward force on the upper part that exactly matches the force of gravity on the upper part. That was true when the building was whole, but after the collpase began it was no longer true, as the collapsing structure simply could not transfer an equal load to the ground.

Once you're into the collapse, modeling the interactions of all the parts, and trying to sum to a simple Ftotal that you can apply to the entire mass of the building is a fools game. And that's essentially what he's trying to do - he's modeling a huge, complex, interdependent structure as essentially perfectly rigid point masses, and then acting like that is the last word on the physics involved.

Yah, Horatius i just spent like 20 minutes since i saw your post figuring out exactly what you're saying, and YES!. There's an infinite amount of forces acting acting over infinitely small time intervals at an infinite amount of places. All of which need to equal zero! By his method, the building should have collapsed immediately. As soon as the exterior columns we're severed there was an additional force on the core right? Lets say the force went from 100N to 120N! NET FORCE DOES NOT EQUAL ZERO! NET FORCE ON THE CORE IS 20N! THE CORE ACCELERATES! hehe

[Horatius]

Yah, Horatius i just spent like 20 minutes since i saw your post figuring out exactly what you're saying, and YES!. There's an infinite amount of forces acting acting over infinitely small time intervals at an infinite amount of places. All of which need to equal zero! By his method, the building should have collapsed immediately. As soon as the exterior columns we're severed there was an additional force on the core right? Lets say the force went from 100N to 120N! NET FORCE DOES NOT EQUAL ZERO! NET FORCE ON THE CORE IS 20N! THE CORE ACCELERATES! hehe



I'm a little lost here. Are you agreeing with me, or arguing with me?

[Furcifer]

I'm a little lost here. Are you agreeing with me, or arguing with me?

I totally agree with you. While i was trying to figure out exactly what you were saying, i also realized that net force on the core was not zero. i should have broke that up into 2 posts :)

[Furcifer]

shoot, no not totally agree with you. the statement "the collapsing structure could not transfer an equal load to the ground" is a little off. the load transfered wasn't to the ground, but the contact point between the upper and the lower parts, it was uneven. i think that's what you mean right?

[R.Mackey]

I've been staying out of this ridiculous thread, but I have to give my congratulations to beachnut for his excellent photographs, proving once and for all that physics is real... I never figured anyone would go ahead with the experiment, but voila, we have!

Fear the Ninja Wave!

[Bobert]

The OP video proves that drugs are very very bad!

[Bobert]

I wonder if he was sniffing that marker before he started all of his drawings?

[Furcifer]

I wonder if he was using the marker because he ate all his crayons...

[Zep]

His mum won't let him have crayons for just that reason.

[gumboot]

I can provide an answer for Fnet

Here it is...

*drum roll*

Fnet>0

Evidence?

Building fall down.

-Gumboot

[Furcifer]

I think Mackey may have the right idea. My head hurts from trying to come up with analogies. Newton was reluctant to show his work to his peers, and now we're trying to pass this knowledge on through YouTube to CT's? Maybe this is just another lesson in futility. I am therefore accepting defeat. Instead, I will focus all my time on figuring out how beachnut got the squib into the egg. peace