"Freefall"

[GlennB]

http://i26.photobucket.com/albums/c148/Glenn_W_Baron/WTC1feefall.jpg

From "What we saw"
WTC7 on the left.

A little later, the "spire"

http://i26.photobucket.com/albums/c148/Glenn_W_Baron/WTC1collapse4TheSpire.jpg

Any help from physicists gratefully received.

The intermediate shots and timings are available at
http://video.google.com/videoplay?docid=-5370762387415552903

Apologies if you've seen all this stuff before .. it's fairly new to me and still somewhat shocking.

[Brainster]

Yeah, the umbrella effect of the debris debunks the freefall claim pretty conclusively, but that's a nice photo all the same.

As for the Spire, check out 9-11 Eyewitness for a pretty good view of the one from the North Tower. I suspect looking at the angle that it fell, that's what hit the Winter Garden/WFC #3.

[Toro]

But don't tell that to the Foilers!

[Mancman]

Yeah, the umbrella effect of the debris debunks the freefall claim pretty conclusively, but that's a nice photo all the same.

As for the Spire, check out 9-11 Eyewitness for a pretty good view of the one from the North Tower. I suspect looking at the angle that it fell, that's what hit the Winter Garden/WFC #3.

The Winter Garden was hit by perimeter columns though, not core.
http://911research.wtc7.net/wtc/evidence/photos/docs/zomb/speared_bldg.jpg

[einsteen]

The freefall argument is a big misunderstanding of course, they didn't go down as free fall. Even wtc7 doesn't go with free-fall speed, that differs 0.6 seonds.

[60hzxtl]

Winter Garden? So much for "in its own footprint" too!

[Dog Town]

The freefall argument is a big misunderstanding of course, they didn't go down as free fall. Even wtc7 doesn't go with free-fall speed, that differs 0.6 seonds.

Goal Post anyone? That's why they aren't on wheels, in the real world. Hard to move! I would also bet, that by looking at your post's the " free fall "misunderstatement, has been used by you! Just a question, did you time the collapse from when the penthouse started falling? You might wanna check that! Or not...

[einsteen]

I've seen the time sequence from the NIST report

[defaultdotxbe]

I've seen the time sequence from the NIST report
and what did NIST measure the time of?

[einsteen]

free fall would be about 5.95 seconds. The bulk goes in about 6.5 seconds and the total time ( I just rechecked) is about 8.2 seconds then. I'm sure that if you take everything into account (damage of inner structure etc) it will be much more but that is a matter of definition of course, this is the visible collapse.

[GlennB]

The freefall argument is a big misunderstanding of course, they didn't go down as free fall. Even wtc7 doesn't go with free-fall speed, that differs 0.6 seonds.

No it differs several seconds The E penthouse falls into the building several seconds before global collapse.
Why? My guess is that whatever was holding it up is no longer holding it up. Girders and stuff like that.

[Alareth]

No it differs several seconds The E penthouse falls into the building several seconds before global collapse.
Why? My guess is that whatever was holding it up is no longer holding it up. Girders and stuff like that.

That pesky gravity...

[twinstead]

By the way, what is the standard reason given for the so-called demolition of WTC7 by the CTs?

For the life of me I can't see any reason at all for that particular building to be demolished as part of the Evil Government's Plan. Nobody died, nobody made any money, and it didn't seem add to the terror of the day (some people I've talked to aren't even aware WTC7 fell).

[einsteen]

One thing is sure, it falls because the things that hold it up cannot longer hold it up.

[Pardalis]

One thing is sure, it falls because the things that hold it up cannot longer hold it up.

words of wisdom

[Alareth]

By the way, what is the standard reason given for the so-called demolition of WTC7 by the CTs?

For the life of me I can't see any reason at all for that particular building to be demolished as part of the Evil Government's Plan. Nobody died, nobody made any money, and it didn't seem add to the terror of the day (some people I've talked to aren't even aware WTC7 fell).

Various reasons I've seen revolve around destroying federal documents stored in the building or destroying Guliani's "bunker" to eliminate evidence that the attacks were staged and controlled from there.

[Gravy]

free fall would be about 5.95 seconds. The bulk goes in about 6.5 seconds and the total time ( I just rechecked) is about 8.2 seconds then. I'm sure that if you take everything into account (damage of inner structure etc) it will be much more but that is a matter of definition of course, this is the visible collapse.
Again, your reading comprehension is poor. The NIST time of 8.2 seconds is the time from the start of the collapse of the east penthouse to the START of global collapse, i.e. when the whole roof starts falling. Add your 6.6 seconds to the 8.2 and you've got 14.8 seconds, nearly 2.5 times longer than "freefall."

[Skibum]

Various reasons I've seen revolve around destroying federal documents stored in the building or destroying Guliani's "bunker" to eliminate evidence that the attacks were staged and controlled from there.

Wouldn't it have been easier to just break out the shredder.

[Gravy]

Various reasons I've seen revolve around destroying federal documents stored in the building or destroying Guliani's "bunker" to eliminate evidence that the attacks were staged and controlled from there.
I believe Einsteen was trying to claim that building 7 was pre-wired with explosives in case it needed to be brought down some day due to the kind of irreparable damage it suffered on 9/11. I'd love for him to elaborate on that idea.

[twinstead]

Wouldn't it have been easier to just break out the shredder.

A shredder isn't quite as cool as secretly wired buildings and dark government plots.

You obviously aren't thinking outside the box. ;)

[GlennB]

Various reasons I've seen revolve around destroying federal documents stored in the building or destroying Guliani's "bunker" to eliminate evidence that the attacks were staged and controlled from there.

;)
And this would be the plan of all plans....

Control the Twin Towers CD from a building that's likely to get smashed by many flying steel girders, while all along you're sitting on vast amounts of explosives.
That's got my vote. Oh yes.

[GlennB]

One thing is sure, it falls because the things that hold it up cannot longer hold it up.

Leave the Dark Side, einsteen. You know you want to.

[defaultdotxbe]

Wouldn't it have been easier to just break out the shredder.
this is a good point, because demolishing a building isnt a good way to destroy evidence, papers from the WTC rained down on the streets after the collapse, they found legible paper in the rubble, they were able to reconstruct computer records of trades made at the WTC

now if they really wanted to destroy evidence in WTC7 they should have just left the fires burning for a few days

[Class]

Wouldn't it have been easier to just break out the shredder.

No, because once you shred all the documents,you need to demolish the building to destroy the shredder.

[einsteen]

yes, I got that wrong, I was misled by a paper of someone called Kutla or Kutta and he calculated 8.3 which is near 8.2 for the total time. But NIST's times are before the global collapse. But that internal pre-collapse that happens is of course related with the destroying of the inner structure.

[Horatius]

;)
And this would be the plan of all plans....

Control the Twin Towers CD from a building that's likely to get smashed by many flying steel girders, while all along you're sitting on vast amounts of explosives.
That's got my vote. Oh yes.

Hey, come on, if these plotters were smart, they wouldn't have left all this great video evidence lying around!

[Gravy]

this is a good point, because demolishing a building isnt a good way to destroy evidence, papers from the WTC rained down on the streets after the collapse, they found legible paper in the rubble, they were able to reconstruct computer records of trades made at the WTC

now if they really wanted to destroy evidence in WTC7 they should have just left the fires burning for a few days
Yes, and they also recovered hundreds of hard drives with usable information from the rubble. Somebody should have shredded them.

[MRC_Hans]

Yes, and they also recovered hundreds of hard drives with usable information from the rubble. Somebody should have shredded them.Really? I thought TS123½ said it was all reduced to a fine powder? :rolleyes:

Hans

[Gravy]

Really? I thought TS123½ said it was all reduced to a fine powder? :rolleyes:

Hans
Don't you remember? Hard drives in 2001 were mostly less than 60 microns in size. That was before the computer companies adopted the "large type" ones and zeros as the bit standard.

[CurtC]

Maybe they pieced together the 60-micron powder to reconstruct the drives. Compared to the rest of the 9/11 conspiracy scenario, like hydrogen bombs and hologram planes, that sounds almost plausible.

[Hellbound]

No one has really brought it up, but I'd like to point out a common misconception, as well, using a hypothetical scenario.

An object falls 490m. it takes 11 seconds to fall this far.

Freefall speed would be 10 seconds.

So, what is the percent difference in acceleration?

The Loosers seem to think that 10 seconds would be "almost freefall" in this scenario. The math is a bit different, though.

d = distance (meters) = 490m (in this scenario)
v0 = initial velocity = 0 m/s
t = time (10 seconds, for this hypothetical)
a = acceleration = what we're looking for

d = vot + 1/2 at2
490m = 1/2 * a * (11s)2
490m = 1/2 * a * 121s2
490m = 60.5s2 * a
490m/60.5s2 = a
8.10 m/s2 = a

8.10m/s2/9.8m/s2 = 82.6%

1 second (from 11 to 10) is almost 18% less acceleration, which means 18% less energy. THe same thing can be done with the various times for the WTC towers, and you can use this to determine what percent of the potential energy went into breaking the structure and/or throwing debris, and what to falling. Basically, there's a simpler way to figure this:

(Freefall Time/Actual Fall Time)2 = % of "freefall" acceleration. The rest of the difference between this and freefall is energy available for the rest of the sturcture.

So, let's take WTC 7. We have an actual freefall time of 5.95s. The claim is that it fell in 6.5 seconds. THat gives us a figure of 83.8% of freefall speed. Again, about 16% of the potential energy available for damage to the structure.

Looks a bit different once the math is done, right?

[einsteen]

Glad you notice later that your 82.6% is nothing more than (10/11)^2
Your energy argument doesn't work however, it's no simple matter of one minus the rest,
you should have a model first and then work it out, that isn't simpel.
And there is in fact no potential energy available to break the structure because
it should first be transformed into kinetic energy. In the twin towers it is assumed
the block falls 3.7 meter first and then a fraction of it is used to break the structure
and so on, If there is no initial speed this cannot happen. The twin towers would
stand forever if there was no initial helping hand. A column of steel can never
collapse because of its own weight. The internal forces in matter (electromagnetic in fact) are
much stronger than gravity when we talk about buildings etc. The shockwave in wtc7 is a high
energy impuls, needed to damage the structure. You can understand that because at that moment
it is stil standing and the potential energy is still available, but then it goes down.
The percentage of freefall acceleration or how you want to call it is due to the fact that it is
no intact building that falls because a trap-door is opened, but because al mass want to move
to the bottom and there is some internal resistance.

[MRC_Hans]

And there is in fact no potential energy available to break the structure because it should first be transformed into kinetic energy.

Really?? So if I place weights on a table, I can place as heavy weights as I please, because since there is no kinetic energy to break the legs, it will hold up forever?

Are you sure you didn't miss a bit here?


In the twin towers it is assumed the block falls 3.7 meter first and then a fraction of it is used to break the structure and so on, If there is no initial speed this cannot happen. The twin towers would stand forever if there was no initial helping hand.


They would keep standing, no matter how much the supporting structure was weakened? Are you serious???


A column of steel can never collapse because of its own weight.


On which planet does this apply? Are you crazy or something?


The internal forces in matter (electromagnetic in fact) are much stronger than gravity when we talk about buildings etc.


We should certainly hope so, otherwise all buildings would fall down. What if those internal forces are weakend by something, however? Like by heat?

The shockwave in wtc7 is a high energy impuls, needed to damage the structure.

That and some fire, ehhh? So, now the structure is damaged, according you what you say above, it should still have no problem holding up the weight of the building?? No matter how much it is damaged???

You can understand that because at that moment it is stil standing and the potential energy is still available, but then it goes down.
The percentage of freefall acceleration or how you want to call it is due to the fact that it is no intact building that falls because a trap-door is opened, but because al mass want to move to the bottom and there is some internal resistance.

What are you trying to say by this?

Hans

[GlennB]

.... The twin towers would stand forever if there was no initial helping hand. A column of steel can never collapse because of its own weight.....

What about if it has 2,000 tonnes to support, a fire to soften it and expanding horizontal girders to give a push inwards?

[einsteen]

@MRC_Hans

Let’s not compare apples with oranges, I mean an object that is able to carry itself cannot break spontaneously because of potential energy. Your table example is true of course but as you already proof in your own example you add external forces by adding heavy weights. In this case I was referring to wtc7, the immense building with the steel frame. There is no way this can crush spontaneously, energy should be added, that doesn’t come from potential energy because it is still standing before it collapses. A little bit fire in wtc7 will not weaken the steel and certainly not crush it. Steel is a excellent heat conductor, think about your cooking pan. The damage is far more important than the heat. What would happen if you break a leg of the Eiffel-tower or maybe two or maybe three?

The twin towers would stand indeed if there was no initial high-speed motion. The energy to break a floor (our old friend Greening, I’m a big fan of Greening and that is no joke) comes from the kinetic energy, only a fraction is assumed to be used to break the floor and everything else. I’m serious; if that initial speed was not there it would stand forever.

What I wanted to say with your last quote is that Huntsman difference in acceleration has only to do with a loose bulk of mass falling down and his energy argument has no meaning.

@GlennB

I don’t accept the whole steel frame became weak and if it did then it would be a continuous process. It’s so completely odd that the block at t=0 can move freely a distance of 3.7m. Greening admits this cannot be proved.

[twinstead]

Einsteen, I'm no expert, but there are SO many qualified structural engineers who disagree with you.

This troubles me. What makes them so wrong and you so right?

[einsteen]

That's a good point, at this stage I then should stop and keep my mouth because I surely know my limitations.

(begin CT'er mode)

Assumptions1 -> results1 -> consistent with reality
Assumptions2 -> results2 -> not consistent with reality

hence let's use Assumptions1. The reports are still true and scientific under the specific assumptions

(end CT'er mode)

[MRC_Hans]

@MRC_Hans

Let’s not compare apples with oranges, I mean an object that is able to carry itself cannot break spontaneously because of potential energy.

Ehhr, no. Not as long as it is defined by "being able to support itself", but that is circular. The point is that a structure can break, not because of potential energy, but because of the forces acting on it, if it is weakened sufficiently.


Your table example is true of course but as you already proof in your own example you add external forces by adding heavy weights.


No problem. Just for you, I'll saw into the legs instead.


In this case I was referring to wtc7, the immense building with the steel frame. There is no way this can crush spontaneously, energy should be added, that doesn’t come from potential energy because it is still standing before it collapses.


No energy needs to be added. Structural strength needs to be taken away. Obviously, this will take some energy, but not some that needs to take direct part in the collapse.

A little bit fire in wtc7 will not weaken the steel and certainly not crush it.

How about a LOT of fire? And extensive direct structural damage.


Steel is a excellent heat conductor, think about your cooking pan.


I'm quite sure you know better than this, because that is primary school physics: Iron (and thus, steel), is an extremely poor heat conductor as metals go. This is the reason you can hold a steel rod in your hand while it is red-hot in the other end. Try that with copper :eye-poppi .


The damage is far more important than the heat.


No. If the damage was most important, WTC 7 would have collapsed shortly after sustaining structural damage.

What would happen if you break a leg of the Eiffel-tower or maybe two or maybe three?

What do you think would happen?

The twin towers would stand indeed if there was no initial high-speed motion. The energy to break a floor (our old friend Greening, I’m a big fan of Greening and that is no joke) comes from the kinetic energy, only a fraction is assumed to be used to break the floor and everything else. I’m serious; if that initial speed was not there it would stand forever.

You may be serious, but you remain wrong. A building stands as long as its structure is strong enough to withstand the force of gravity acting on its weight. If you start weakening the structure, the moment you reach the point where it can no longer support the weight, the building collapses. No need for any kinetic energy.

BTW, I hope you are aware that you are arguing that demolitions are impossible?


What I wanted to say with your last quote is that Huntsman difference in acceleration has only to do with a loose bulk of mass falling down and his energy argument has no meaning.


I know. You are wrong.

I don’t accept the whole steel frame became weak and if it did then it would be a continuous process.

It was a continuous process. The frame was continuously weakened. At the point where it became weaker than the force acting on it, it gave way, the building above it started to move downwards, and then kinetics took over.

It’s so completely odd that the block at t=0 can move freely a distance of 3.7m.

At t=0? At t=0, it started moving, because its support failed. When it had moved 3.7m, it had accelerated somewhat and impacted on the structure below.

I think you are being deliberately obtuse, here. If a structure supporting a weight is being weakened, there will come a point when it can no longer support that weight. What will, in your opinion, happen then?

Hans

[einsteen]

Dear Hans, steel and copper are good heat conductors. Copper better than steel but steel is a very good heat conductor.

I would expect the Eiffel tower would topple, that's also what the controlled demolition experts do.

Ok Hans, wtc7 was damaged from the beginning and the heat made it weak, after a certain point everything broke inside ? maybe I should put my books out of the dust but I've never heard about this effect.

[MG1962]

The twin towers would stand indeed if there was no initial high-speed motion. The energy to break a floor (our old friend Greening, I’m a big fan of Greening and that is no joke) comes from the kinetic energy, only a fraction is assumed to be used to break the floor and everything else. I’m serious; if that initial speed was not there it would stand forever.

What is being forgotten is load bearing. Each floor of the tower was rated at 1100 tons. Once the load on that floor exceeds that level, it will break. That is the whole point of progressive and pan cake collapses. As a floor gives way, the floor below tries to take up the load, snaps, then the next floor and so on. The process gathers speed as it continues. The rubble from above is accellerating, and the demand on the surviving floors is becoming greater with each moment

[Crazy Chainsaw]

Dear Hans, steel and copper are good heat conductors. Copper better than steel but steel is a very good heat conductor.

I would expect the Eiffel tower would topple, that's also what the controlled demolition experts do.

Ok Hans, wtc7 was damaged from the beginning and the heat made it weak, after a certain point everything broke inside ? maybe I should put my books out of the dust but I've never heard about this effect.

Let us also not forget about the complex chemical reactions of steel with the Compounds created in the fires we can not use the estimates of the strengths of the resistance for undamaged steel.

We also have to talk about hydrogen Embrittlement, And Carbon reactions with the oxide coatings, the steel itself was a source of heat in the fires and would have damaged itself.
You have a lot of complex chemical reactions that most people are over looking.

http://www.corrosion-doctors.org/Forms/embrittlement.htm

http://www.chemguide.co.uk/inorganic/extraction/iron.html

Also remember that sulfuric Acid was produced by the fires as the Diesel burned, which would have cleaned the metal and cause new oxidation and exposed new metal to Hydrogen Embrittlement.

People tend to forget that steel is a reactive metal itself, It oxidizes and reacts with other elements when heated.

I have seen the effects of high sulfur petroleum products on even stainless steel, when burning, Although I am not a chemist, I have no doubt but that the reactivity of the compounds involved played a key factor in the collapses of all the buildings.

[einsteen]

It becomes really difficult yeah.

[MRC_Hans]

Dear Hans, steel and copper are good heat conductors. Copper better than steel but steel is a very good heat conductor.

http://en.wikipedia.org/wiki/Thermal_conductivity#Some_typical_thermal_conducti vities_.28k_values.29

Steel conducts heat more than 10 times less effectively than copper. What does this mean? It means that unlike copper, parts of a steel structure can be heated to considerable temperatures while others stay cool.

ETA: My cooking pan is aluminium (almost as good a conductor as copper), but the handle is steel. Yet I can easily touch it.


I would expect the Eiffel tower would topple, that's also what the controlled demolition experts do.


And?

.... Oh, I know where you're going, and if you wanna do that, I'm game :D .

Ok Hans, wtc7 was damaged from the beginning and the heat made it weak, after a certain point everything broke inside ? maybe I should put my books out of the dust but I've never heard about this effect.

Everything? No, enough supporting structures broke so that the building could no longer support its own weight. This is called a catastrophic break-down.

Let me spell it out to you:

Suppose a building has 50 columns holding it up. Now, of course a building will be dimensioned with a fair safety margin. So actually, 30 columns are enough to support it. Now, let's say some accident destroys 10 columns. Since each of the columns can carry 1/30 of the building, and they only now carry 1/40, the building keeps standing. Now, fire is weakening a number of the columns. At some point, one is weakened beyond the 1/40 of the building weight it is carrying, so it breaks or bends. The building may sag, but since the rest of the supports can still carry the 1/39 of the building they are now carrying, it stays up. Nnext column fails, now they all have to carry 1/38. Next etc... At the point where we reach 1/30, the next failing column will result in the rest being overloaded, and they will fail in an ever accelerating succession, as more and more suppoers get more and more overloaded.

...

You can make an experiment to show this:

Take something heavy, for instance a bucket of water. Suspend it with a number of thin threads, sewing yarn or the like. It needs to be so that it takes several strings to carry its weight, but you have more than enough.

Now, cut one string at a time. What happens? At some point, the remaining ones all break, in rapid succession, and the weight falls.

Hans

Edited for codes.

[tsig]

It becomes really difficult yeah.

Not difficult at all. Gravity just recaimed her own.

[Hellbound]

Everyone else has pretty well covered your "points", einsteen. But I'll add a bit.

My calculations were based on the assumption of a collapse starting. THey were intended to show that there was a significant difference between the 6.5 seconds it fell and freefall. So the freefall argument is moot.

The energy statements were in regards to the multiple times you've talked about how much energy needed to be taken away to do other things besides accelerate downwards. The proportion of actual fall time squared to freefall time squared calculated above should be identical to the proportion of total energy to the energy used for downward acceleration. This places a cap on the amount of energy available for other actions, such as tossing debris or breaking additional supports.

Of course, I should have explained this better earlier, but I seriously thought that you had at least a basic knowledge of physics. I will no longer assume you have had a high-school physics education, so this type of confusion should not occur again.

[MRC_Hans]

In all fairness, Einsteen is not a "free-faller".

Hans

[Hellbound]

In all fairness, Einsteen is not a "free-faller".

Hans

Au contraire.

He is, he just doesn't realize it. It's the same basic argument, about there being not enough energy available to break the structure and fall as fast as it did. Just because he agrees it wasn't freefall doesn't change the fact that he's making the same argument, and has the same lack of understanding and avoidance of math and physics that they show.

So while technically he may not be a "freefaller", his arguments are identical.

[Cuddles]

I would expect the Eiffel tower would topple, that's also what the controlled demolition experts do.

I'm surprised no-one else addressed this. Do you honestly believe demolition experts topple buildings over sideways?

[einsteen]

Hans I understand your column example but do you remember that movie posted recently about a CD that fails an entire block stays intact, for wtc7 we see it completely disappearing and collapsing to the ground at all levels. And again steel is a very good heat conductor enough to conduct. Ever wonder why steel feels cold when you touch it?
Copper would be much better but steel has the purpose it is strong, copper not. Steel conducts heat good enough to get no gradient if you heat it at one side.

Cuddles, yes they topple buildings, an expert told it in an interview.

Huntsman, again the potential energy is not used to break the structure but to accelerate the mass downwards in the wtc7 case

[Hellbound]

Huntsman, again the potential energy is not used to break the structure but to accelerate the mass downwards.

Are you really this ignorant of physics?

You still fail to understand the issue.

If potential energy is not used to break the structure, then the building should have fallen at a speed as if freefalling, and you refute your own theory.

Part of the structure was weakened enough to allow the structure to fall. The gravitational potential energy accelerated the falling part downward. This falling part would A) impact other parts that had not yet begun to fall, transferring some of it's energy and causing additional structure and support to break and B) initiated impacts that threw out debris and dust. The total energy avaialble to the collapse is equal to the total gravitational potential energy in the structure. This is an upper limit on the amount of energy available, in total, from collapse initiation until the collapse is over.

I'm sorry you don't understand this, but if you truely cannot grasp what is a very basic concept regarding physics and conservation of energy, there's no use going further. You have shown yourself to not only be ignorant, but willfully so, as it would take very little time or education to understand this type of error.

[Cuddles]

[Cuddles, yes they topple buildings, an expert told it in an interview.

So all those buildings that have been demolished over the years by collapsing them vertically so they don't damage anything nearby are in fact hoaxes on the part of the conspirators to make us believe that the twin towers could collapse the same way? Or are you just talking out of the wrong hole?

[MRC_Hans]

Hans I understand your column example but do you remember that movie posted recently about a CD that fails an entire block stays intact, for wtc7 we see it completely disappearing and collapsing to the ground at all levels.

So what? Buildings are different. The building in that CD was not a homogenous structure, perhaps it had even been built in several sequences.

Are you now saying that because WTC 7 falls differently from a movie you saw of one CD, it means that WTC 7 was a CD? Or what exactly is it you are claiming?


And again steel is a very good heat conductor enough to conduct. *snip*
Steel conducts heat good enough to get no gradient if you heat it at one side.


Well, basically that is wrong. There will always be a gradient. But what about it? The point is that a fire can heat parts of the steel structure so that it looses strenght.


Cuddles, yes they topple buildings, an expert told it in an interview.


What exactly do you mean by "topple"?

Huntsman, again the potential energy is not used to break the structure but to accelerate the mass downwards.

No. The the force of gravity is what accelerates the mass. The potential energy is the product of the weight and the elevation. This may be nitpicking, but we might as well get the terms right.

Hans

[CurtC]

If potential energy is not used to break the structure, then the building should have fallen at a speed as if freefalling, and you refute your own theory.
The free-fallers always seem to make the mistake of figuring if gravitational potential energy is used to accelerate something (conversion to kinetic energy), then there is no energy left for destroying it. It seems to me that, at least in the case of WTC7, they're overlooking the fact that all that kinetic energy, when it hits the ground, is spent breaking things up. So you can have both near free-fall speeds and energy to destroy the materials, just at different times.

Einsteen, since the kinetic energy of the falling mass came to an end when it hit the ground, that energy gets used to destroy stuff. It's that simple in the case of WTC7.

[Hellbound]

The free-fallers always seem to make the mistake of figuring if gravitational potential energy is used to accelerate something (conversion to kinetic energy), then there is no energy left for destroying it. It seems to me that, at least in the case of WTC7, they're overlooking the fact that all that kinetic energy, when it hits the ground, is spent breaking things up. So you can have both near free-fall speeds and energy to destroy the materials, just at different times.

Einsteen, since the kinetic energy of the falling mass came to an end when it hit the ground, that energy gets used to destroy stuff. It's that simple in the case of WTC7.

Yes, this is true as well :) On impact, the kinetic energy gets converted to mechanical and heat energy (and probably others).

Good catch! I'd missed that one (but then again, I also don't claim to know more than the physics and engineering experts...well, not usually ;)).

[einsteen]

Cuddels, they topple buildings. Experts like Brent Blanchard and also Jowenko can tell you that, I will not post movies from it because you can find it if you want.

Huntsman, I rechecked and another expert Loizeaux, he says in fact:
The explosives are used as the catalyst and gravity is the engine.

Once it goes it goes, the tremendous amount of kinetic energy will break extremely strong structures. I was more referring to the initial moment, potential energy doesn't break the complete structure, it is the kinetic energy/momentum etc. Strictly speaking I was wrong that I said that the potential energy is only used to get the building down because once it is transformed to kinetic energy that is also used to break some other stuff.
And energy is energy isn't it. Let me correct that.

And in fact Greening already shows that once you only need a fraction of the kinetic energy (ok you are right: comes from the potential energy) to break the structure. The collapse time in the TT case differs only a little bit.

Let me end this posting by noting that for wtc7 both a controlled demolition and a structural failure are consistent with the laws of physics.
However if you know how difficult the technique is (there are only about 20 CD companies) to end with a pile of rubble then I'm more thinking about the first one.

I copy paste something from howstuffworks:

Blasters might also overestimate the amount of explosive power needed to break up the structure, and so produce a more powerful blast than is necessary. If they underestimate what explosive power is needed, or some of the explosives fail to ignite, the structure may not be completely demolished. In this case, the demolition crew brings in excavators and wrecking balls to finish the job. All of these mishaps are extremely rare in the demolition industry. Safety is a blaster's number-one concern, and, for the most part, they can predict very well what will happen in an implosion.

[R.Mackey]

Let me end this posting by noting that for wtc7 both a controlled demolition and a structural failure are consistent with the laws of physics.
However if you know how difficult the technique is (there are only about 20 CD companies) to end with a pile of rubble then I'm more thinking about the first one.
It's only consistent "with both" if you ignore the vast majority of evidence. The only things you're looking at are one view that shows the top of the building upwind, de-emphasizing the lean of the building, the structural damage, and the huge fires; and some vague notions about the debris pile afterward.

You are conveniently ignoring the several hours of structural degradation noticed by the Fire Department while the thing was burning brightly, the lack of any sound or sight of explosives detonating, the lack of any residue or structural members that show evidence of cutting, and the obvious fact that explosives would not have survived the fire. If you keep this in mind, you will see that structural failure is the only conclusion.

Picking and choosing evidence to fit a preconceived notion is not scientific. We've explained this to you over and over again.

[einsteen]

But Mr. Mackey have you seen the movie "the building is about to blow up" and also the movie that people where told to leave because... The women with the baby in arms didn't stand there for 7 hours. And there is audio evidence of a women who mentiones a first blast to weaken the structure. There is a guy who talks about a shockwave and windows blowing out.

The lean of the building ? The licensed blasters topple buildings like tree trunks by weakening only one side of the building, there is nothing to be de-emphasized about that. And there are a coupe of experts convinced about the CD.

It's indeed strange that Jowenko for example says that explosives would go of immediately in the TTs and that it takes a year to wire but that the wtc7 could be done quickly because of the few columns it has. I wish the interview was much longer, why don't journalist go to all companies to ask, the VARA (Dutch channel that I don't like politically but that's not relevant) said that nobody has ever asked it. That can't be true, further if the fires are localized you can savely go to the basement of course.

[R.Mackey]

But Mr. Mackey have you seen the movie "the building is about to blow up" and also the movie that people where told to leave because... The women with the baby in arms didn't stand there for 7 hours. And there is audio evidence of a women who mentiones a first blast to weaken the structure. There is a guy who talks about a shockwave and windows blowing out.
Are you claiming that you have evidence of explosives?

What we know is that WTC 7 was fully evacuated, all firefighters pulled well back in a defensive cordon, hours before it fell.

You expect me to believe that a woman with a baby in her arms stood close enough, for that long, to have been able to tell it was "blown up?" You pick some random guy who claims a "shock wave," one that didn't show up in the same video you watched (it would have broken the windows all at the same instant, no such thing), as more credible than the entire FDNY?

You're grasping at straws, and you're doing it because you're biased. If the effects you describe were so obvious that these people could correctly identify them, it would have been obvious to the literally hundreds of people, professionals, who were intently watching the structure. So they're all either idiots or liars, but these two random people in some bit of Internet video hold the secret? That's your story, right?


The lean of the building ? The licensed blasters topple buildings like tree trunks by weakening only one side of the building, there is nothing to be de-emphasized about that. And there are a coupe of experts convinced about the CD.
Depends on the building. Some they do and some they don't. It works much better for short buildings, because the moment arm is shorter and not nearly as much angular momentum must be imparted. It's unlikely a pro blaster would drop WTC 7 in that fashion. Same with WTC 1 and 2.

Besides, this is a non-sequitur. WTC 7 was leaning for hours before it fell. FDNY had a transit on it measuring the lean. CD's do not gradually tip buildings over a period of hours.

Just because some other process could also induces a lean does not mean that a lean necessarily implies that other process. As I have already explained, there are other clues that rule out CD. You have no point.


It's indeed strange that Jowenko for example says that explosives would go of immediately in the TTs and that it takes a year to wire but that the wtc7 could be done quickly because of the few columns it has. I wish the interview was much longer, why don't journalist go to all companies to ask, the VARA (Dutch channel that I don't like politically but that's not relevant) said that nobody has ever asked it. That can't be true, further if the fires are localized you can savely go to the basement of course.
Irrelevant.

Placement of explosives would not have survived the fire.

You're assuming, not only were explosives placed, but the people who put them there knew exactly where the fire would start and how it would evolve. Obviously these people have a working crystal ball, in addition to explosives that leave no residue, make no noise, break no windows, trigger no seismographs, bring the building down from the inside first, and fool the combined structural and demolitions experts of NIST and the entire world.

If that sounds paranoid to you, it's because it is.

As before, you have no evidence, only bias.

[Oliver]

But Mr. Mackey have you seen the movie "the building is about to blow up" and also the movie that people where told to leave because... The women with the baby in arms didn't stand there for 7 hours. And there is audio evidence of a women who mentiones a first blast to weaken the structure. There is a guy who talks about a shockwave and windows blowing out.

The lean of the building ? The licensed blasters topple buildings like tree trunks by weakening only one side of the building, there is nothing to be de-emphasized about that. And there are a coupe of experts convinced about the CD.

It's indeed strange that Jowenko for example says that explosives would go of immediately in the TTs and that it takes a year to wire but that the wtc7 could be done quickly because of the few columns it has. I wish the interview was much longer, why don't journalist go to all companies to ask, the VARA (Dutch channel that I don't like politically but that's not relevant) said that nobody has ever asked it. That can't be true, further if the fires are localized you can savely go to the basement of course.

Did you see the movie "Titanic"? :D Facts, please.

[einsteen]

Never seen Titanic.

R.Mackey but then there must be an explanation why people walk away from the building saying "building is about to collapse", this is not some random video, it is the only few video material from eyewitnesses

http://www.youtube.com/watch?v=CwjmqkjwnvQ

[Oliver]

Never seen Titanic.

R.Mackey but then there must be an explanation why people walk away from the building saying "building is about to collapse", this is not some random video, it is the only few video material from eyewitnesses

http://www.youtube.com/watch?v=CwjmqkjwnvQ

Well, if i just saw WTC1 and 2 collapsing - i would be more then sceptic about building 7 with it´s heavy fires and the reported damage, wouldn´t you?

[R.Mackey]

R.Mackey but then there must be an explanation why people walk away from the building saying "building is about to collapse", this is not some random video, it is the only few video material from eyewitnesses

http://www.youtube.com/watch?v=CwjmqkjwnvQ
So who are the people on the video, and what are their credentials? When was the video taken? If you can't answer that, it is a random video.

FDNY concluded at about 1:30 in the afternoon that WTC 7 was going to fall. It fell over three hours later. So logically anyone nearby should have figured it out. This was not a secret.

I don't understand what you find so mysterious.

If it was a demolition, then the only people who "knew" it was going to collapse would have been the people in on the plot. That means the people speaking on the video. In that case, your video would be tantamount to an admission of complicity.

Do you understand just how insane this is?

[Loss Leader]

Do you understand just how insane this is?

I am willing to wager that he does not.

[jujigatami]

At somewhere around 2pm on 9/11 I walked away from WTC7 saying it was going to collapse.

It was the massive amount of damage to the building, the massive fire, and the fact that it was leaning over that gave me a clue.

Everyone looking at the building saw ot was going to come down.

[einsteen]

It's a compilation made by CNN about wtc7, this is a raw capture from CNN. I don't know who those guys are, I wasn't there.
It doesn't look like something secret, everyone had to leave the environment. Did you hear the explosion and the multiple echo,
well we have at least the sound of an explosion (I mean another) at 911. I don't know what is insane about it, we should at least
have some consistencies. You understand this is a medium for CT's. I have at least some questions and don't simply ignore video material if I was biased to the official theory.

ps. "about to collapse" is not "about to blow up"

[Loss Leader]

ps. "about to collapse" is not "about to blow up"

Yes, but you will notice that the building didn't blow up. WTC7 did not explode or blow up in any way. If it were really about to blow up, the firement and others in the video would have been running like hell.

Instead, they are moving away from the zone in which debris might be expected from a collapse. So, whether they said "blow up" or "collapse," the video shows that the building did in fact collapse.

The fact that hyperbolic statements from witnesses ("blow up," "explosions," or "using planes as missiles") are more important than the observation of the events of that day is one of the things that I understand least about the CTists.

[einsteen]

For those who are deaf

http://www.youtube.com/watch?v=h-L-jfCGhoY

[MG1962]

For those who are deaf

http://www.youtube.com/watch?v=h-L-jfCGhoY

Wow - Well I am convinced. And who would have thought - Not even the X files would have been capable of such a radical idea

[einsteen]

Well that Boom Boom Boom sound in this video

http://www.whatreallyhappened.com/IMAGES/wtc7_blow_up.wmv

is just a minor issue, let's forget about it and forgot whoever says "blow up" whatever that means, maybe the cameraman was blowjobbed

[Loss Leader]

Well that Boom Boom Boom sound in this video

http://www.whatreallyhappened.com/IMAGES/wtc7_blow_up.wmv

is just a minor issue, let's forget about it and forgot whoever says "blow up" whatever that means, maybe the cameraman was blowjobbed


You know, einsteen, I was once watching a guy and he started yelling and screaming that there was a Tyranasaurus Rex. I didn't believe him because those were just words. But then I saw with my own eyes a T Rex. That finally convinced me that it was real.

Or would have until the credits rolled and I realized it was just a movie. Your senses can be fooled. People's words can be less than perfect. But, in the end, if something is impossible then it cannot possibly have happened.

[Pardalis]

Oh no, the NWO has arrived in Laval?

http://www.macleans.ca/topstories/news/shownews.jsp?content=n093049A

One witness said the accident caused a bang that "sounded like the explosion of a 50-kilogram bomb."

:boxedin:

[Oliver]

For those who are deaf

http://www.youtube.com/watch?v=h-L-jfCGhoY

Hallelujah!

I just got that MI-LIHOP Guy out of my head! I don´t care if you´re a man or a women... I love you!

No kidding - Thank you so muchfor the link, Einsteen.

[geni]

Is this a bad time to mention that freefall is a furry webcomic?

http://freefall.purrsia.com/default.htm

[AK-Dave]

Steel conducts heat good enough to get no gradient if you heat it at one side.

We have some very tall highway lights at some of the major entrance and exit ramps on the highway near me. They are constructed of rather thick steel - I saw the segments before they were assembled. They all lean away from the sun. It's most noticable in the winter, since the sunlight is at a low angle all day. No matter what direction the sun is coming from, they always lean away. Why is that? You'd think such a great conductor of heat would be able to transfer enough heat from one side of the pole to the other fast enough that there wouldn't be a thermal gradient. And that's just from sunlight. I wonder how much they would bend of you had a multi-story fire burning on one side of them?

[R.Mackey]

Well that Boom Boom Boom sound in this video

http://www.whatreallyhappened.com/IMAGES/wtc7_blow_up.wmv

is just a minor issue, let's forget about it and forgot whoever says "blow up" whatever that means, maybe the cameraman was blowjobbed
einsteen, this is getting awfully tedious, and you have some cheek implying that we are all deaf. If you want us to take you seriously, you are going to have to be much more respectful.

For now, since this appears to be all the evidence you have, just answer this question:

Which is more likely?

1. The person speaking was using "blow up" as a figure of speech, referring to WTC 7 collapsing

2. The person speaking knew that, incredibly, there were bombs in the building, and they were going to be detonated

Which one? Explain your answer.

[R.Mackey]

Is this a bad time to mention that freefall is a furry webcomic?

http://freefall.purrsia.com/default.htm
Great webcomic. I've been following it for years. The science is pretty decent, and as an AI researcher, I find the ethical robot discussions fascinating... [/derail]

[Alareth]

Oh no, the NWO has arrived in Laval?

http://www.macleans.ca/topstories/news/shownews.jsp?content=n093049A

One witness said the accident caused a bang that "sounded like the explosion of a 50-kilogram bomb."

:boxedin:

A whole 50 kilograms? Wow.

[einsteen]

R.Mackey, no offense of course, I know the people here are in general skilled people who I respect, this was just a slip of the tongue. It could indeed be a figure of speech. But there is also a correlation between that figure of speech and the explosion sound, which is not a kind of crunch sound as a result of structural failure and it happened before the global collapse. But I stop with this now here.

AK-Dave, the gradient will be there but to be precise I mean that heat conduction will work as a kind of buffer.

Loss Leader, there are also groups of people who saw UFO's I don't believe them, they have no evidence, even if 1000 people say it it is worthless if there is no evidence. The problem then is if those folks are experts we have to believe them...??

[Gravy]

R.Mackey, no offense of course, I know the people here are in general skilled people who I respect, this was just a slip of the tongue. It could indeed be a figure of speech. But there is also a correlation between that figure of speech and the explosion sound, which is not a kind of crunch sound as a result of structural failure and it happened before the global collapse. But I stop with this now here.

AK-Dave, the gradient will be there but to be precise I mean that heat conduction will work as a kind of buffer.

Loss Leader, there are also groups of people who saw UFO's I don't believe them, they have no evidence, even if 1000 people say it it is worthless if there is no evidence. The problem then is if those folks are experts we have to believe them...??
einsteen,
Not a single person who was on the scene when WTC 7 collapsed described hearing or seeing anything resembling explosives. Not the firemen, not the EMTs, not the engineers, not the explosives demolitions experts. Nor was a single piece of evidence indicating the placement or use of explosives found.

Please stop this foolishness. It's childish and it's deeply disrespectful of the people who work their butts off to achieve expertise in their fields.

ETA: Answer your own question: are there experts in UFO identification?

[MRC_Hans]

Einsteen, I notice you are getting all jokey and fuzzy. I have noticed this kind of evasion before (in this case it might be unintentional, I don't know you well enough yet). However, let's not waste time:

You have made some claims and they have been countered. What exactly is your present position?

- What exactly do you claim happened to the WTC, and what is your evidence for that claim?

I for one am not going to waste time with someone who just drops fuzzy half-arguments all over the place, so let's have some focus now, OK?

Hans

[Gravy]

I don't think we're going to see that from einsteen, Hans. We've been calling him on this behavior since he started posting here.

[einsteen]

Hans, last days what I think differs from hour to hour, sometimes I believe in the official wtc7 story and sometimes I don't, you understand that the posts here are only the moments that I don't. But I will stop annoying you with that building until there are other views by the experts. Let's wait for the final report.

later

[Gravy]

Hans, last days what I think differs from hour to hour, sometimes I believe in the official wtc7 story and sometimes I don't, you understand that the posts here are only the moments that I don't. But I will stop annoying you with that building until there are other views by the experts. Let's wait for the final report.

later
It's good that you want to read the final NIST report. However, not once did you state your objections to the interim report on WTC 7, or state why you believe all the accounts from the experts who were on the scene are questionable. Nor were you able to provide a rational explanation of why anyone would have wanted the building to collapse.

Thanks for wasting our time.

[einsteen]

Nor were you able to provide a rational explanation of why anyone would have wanted the building to collapse.


The damned terrorists did it Gravy, they hate our freedom

[MRC_Hans]

Hans, last days what I think differs from hour to hour, sometimes I believe in the official wtc7 story and sometimes I don't, you understand that the posts here are only the moments that I don't. But I will stop annoying you with that building until there are other views by the experts. Let's wait for the final report.

laterMmmm, OK. If your fuzzy posts really reflect confusion, I apologize. However, let's try to clear that confusion, then:

There is already an official report out, and though some parts are apparantly still pending, they are not likely to change the general conclusion on any important points.

So, what points in the official conclusion (the so-called OCT) give you cause for doubt?

Hans

[Gravy]

The damned terrorists did it Gravy, they hate our freedom
Why are you unable to take these questions seriously?

[einsteen]

Hello Hans,

http://wtc.nist.gov/pubs/WTC%20Part%20IIC%20-%20WTC%207%20Collapse%20Final.pdf

This is indeed a very detailed overview of the damage etc. I've also seen some of the TT reports, that contain hundreds of pages, full with temperature diagrams and damage of all trusses but it is only Greening who under some assumptions shows a calculation with math. I know that the exact calculations cannot be done, even numerical methods are very sensitive to small changes in assumptions etc. and one admits that some initial values will remain unknown forever. The wtc7 report does (maybe someone can point me to it or an other report) not yet talk about the global collapse and the 6.5 seconds. The report of Kenneth Kutler is a similar report as Greening although I'm sure he will be sweeped to the CT corner, he is probably already there because he seems to be on the BYU website, but math is math and is reproducible by any scientist, the same of course for the 10 feet of NIST reports but I don’t believe that the actual collapses are treated in detail, only the causes of failure, it looks like one is not interested in what happens then, because it is just the consequence of failure.

[Gravy]

The wtc7 report does (maybe someone can point me to it or an other report) not yet talk about the global collapse and the 6.5 seconds.
That's because the building didn't collapse in 6.5 seconds, as you know. And the report does talk about the global collapse. That's the purpose of the report.

Why do you lie, einsteen?

And why are you unable to take these questions seriously?

[MRC_Hans]

Hello Hans,

http://wtc.nist.gov/pubs/WTC%20Part%20IIC%20-%20WTC%207%20Collapse%20Final.pdf

This is indeed a very detailed overview of the damage etc. I've also seen some of the TT reports, that contain hundreds of pages, full with temperature diagrams and damage of all trusses but it is only Greening who under some assumptions shows a calculation with math. I know that the exact calculations cannot be done, even numerical methods are very sensitive to small changes in assumptions etc. and one admits that some initial values will remain unknown forever. The wtc7 report does (maybe someone can point me to it or an other report) not yet talk about the global collapse and the 6.5 seconds. The report of Kenneth Kutler is a similar report as Greening although I'm sure he will be sweeped to the CT corner, he is probably already there because he seems to be on the BYU website, but math is math and is reproducible by any scientist, the same of course for the 10 feet of NIST reports but I don’t believe that the actual collapses are treated in detail, only the causes of failure, it looks like one is not interested in what happens then, because it is just the consequence of failure.

Two buildings were hit by jet-liners, were set on fire, and subsequently collapsed.....

- We know they were hit by planes. We know there were extensive fires (most of the world watched in real-time).

- We know they collapsed.

- Nobody has been able to come up with a remotely plausible alternative explanation for why they should collapse, nor have they uncovered any evidence for an alternative cause.

What keeps you from concluding that they collapsed because og the planes hitting them, and the subsequent fires?

One building was severely damaged by falling parts from buildings collapsing nearby. Fires burned inside the building for hours. The building subsequently collapsed.

- Testimony from firefighters and construction specialists show that, after seeing the extent of damage, they expected the building to collapse.

- As a result, fighting the fires was abandoned, and the building was evacuated, and everybody stood back waiting for the collapse.

- Nobody has been able to come up with a remotely plausible alternative explanation for why it should collapse, nor have they uncovered any evidence for an alternative cause.

What keeps you from concluding that it collapsed due to the damages it had suffered?

Hans

[einsteen]

Gravy, I never lie and please don’t intimidate me. I was talking about the coming down of the damned building.
I guess you also disagree with 14.7 seconds for the total collapse because you mention 18 seconds in that Alex Jones movie. The total period of the seismic data I assume. It’s a matter of definition Gravy, it’s a matter of definition. Think about your blood pressure.

@Hans, they expected wtc7 to collapse and it collapsed. The expected indeed happened in contrast to the TTs where no-one expected
it. Allright then (Arkan would call that after-911 knowledge). As I already said it is time to stop with this here, I don't want
to get the Chris-effect. And I admit that if 98% of the experts agree with that and 2% don't there is a high chance the first is
right it doesn't make my position strong, logically it is still no proof but i now really stop, thanks for the time.

[Loss Leader]

Nor were you able to provide a rational explanation of why anyone would have wanted the building to collapse.

Gravy, there is a simple rational explanation for why "anyone" would have wanted the building to collapse. After immense damage from the fall of the towers and hours of fire, WTC7 was a weakened and unsafe building. Standing, it was a danger to the life of every person within a one block radius. I think you will remember that WTC5, which did not collapse, was later demolished because it could not be salvaged. Under those conditions, hoping for a quick collapse that day would be prudent and sensible compared to trying to isolate the building and still have an increasing number of people return to the area over the next several days.

Get your facts straight before issuing challenges.

[/sarcasm mode]

[R.Mackey]

R.Mackey, no offense of course, I know the people here are in general skilled people who I respect, this was just a slip of the tongue. It could indeed be a figure of speech. But there is also a correlation between that figure of speech and the explosion sound, which is not a kind of crunch sound as a result of structural failure and it happened before the global collapse. But I stop with this now here.
I'm thicker skinned than that, no worries, but you didn't answer my question.

Was the "blow up the building" thing a figure of speech, or "Evidence" that WTC 7 was demolished? Pick one.

The more you evade, the harder it gets to take you seriously.

[einsteen]

It doesn't stop of course...

No R.Mackey it is no evidence. People can say everything. I've enough mathematical background to know what a real proof is.
But I still cannot place the sound of the explosion (with echo's 0.332 sec later) into context, too bad it is a CNN compilation, but it looks as a genuine CNN show. I cannot explain this sound also not within the context
of the official story. We can ignore it or try to find a simple explanation. I'm sure there wil be found one, that's the whole purpose of the debunking sites, isn't it ?

My biggest mistake ever was that movie of the two towers that looked like one. That was a typical example of misleading people by giving false
information (I'm still angry about that, it was also a little bit my fault that it was a CT'ers point of view, I even did not know about debunking sites at that time), but then you see what it really is and say... ooh stoopid.
There is still a lot of work to do for the debunkers, I think it will not stop easily.

[Gravy]

Gravy, I never lie and please don’t intimidate me.

I guess you also disagree with 14.7 seconds for the total collapse because you mention 18 seconds in that Alex Jones movie.
That's a lie.

You even lie about lying. Good work, einsteen.

[Gravy]

@Hans, they expected wtc7 to collapse and it collapsed. The expected indeed happened in contrast to the TTs where no-one expected
it. Allright then (Arkan would call that after-911 knowledge).
The collapse of one building on 9/11 was unexpected: the south tower. When that collapsed, the order was given to evacuate the north tower. Later, NYPD helicpoter pilots reported the danger of imminent collapse because the exterior columns were bowed.

[R.Mackey]

No R.Mackey it is no evidence. People can say everything. I've enough mathematical background to know what a real proof is.
I agree. The person in the video saying that WTC 7 was "going to blow up" is not proof or even evidence of anything. Let's move on now.

But I still cannot place the sound of the explosion (with echo's 0.332 sec later) into context, too bad it is a CNN compilation, but it looks as a genuine CNN show. I cannot explain this sound also not within the context
of the official story. We can ignore it or try to find a simple explanation. I'm sure there wil be found one, that's the whole purpose of the debunking sites, isn't it ?
I'll let you take a crack at this:

Describe the sound you hear. Describe when it occurs, if that correlates to any other behavior, etc.

Now describe what it possibly might be. There are many possibilities.

Now take each of those possibilities and see what each of them, if it were true, would imply.

Finally, take those lists and see which are impossible or improbable based on the other facts on the scene.

If you do this correctly, you'll be left with several very mundane possibilities, and few to no sinister ones.

[Gravy]

einsteen is playing dumb. I don't get the game. The subject of "context" of the loud noise heard on the video came up just yesterday (http://forums.randi.org/showpost.php?p=1970921&postcount=35).

A bang and two echos? And when did the building fall down again?

Einsteen, you do realize that things were blowing up, especially cars, all over the place after the towers came down, don't you? In addition, lots of debris was falling from WTC 7, which must have made noise.

[R.Mackey]

einsteen is playing dumb. I don't get the game. The subject of "context" of the loud noise heard on the video came up just yesterday (http://forums.randi.org/showpost.php?p=1970921&postcount=35).
Yeah, I know.

Some people are playing, and some aren't. I'm still trying to be optimistic. einsteen was good enough to understand that the "blow up" comments on the video don't mean a thing, so perhaps we'll be able to build on that little victory.

Hang in there, Gravy, we're making progress, you most of all.

[LashL]

Sort of off topic, but why is it that CTists insist upon saying that WTC7 fell in 6.5 seconds on the basis of their own viewing of videos that don't progress further than approximately the bottom 20 floors of the building?

They all seem to base their "timing" on the same video which doesn't show anything below 20 stories and they stop their "timer" at that point.

[Gravy]

Sort of off topic, but why is it that CTists insist upon saying that WTC7 fell in 6.5 seconds on the basis of their own viewing of videos that don't progress further than approximately the bottom 20 floors of the building?

They all seem to base their "timing" on the same video which doesn't show anything below 20 stories and they stop their "timer" at that point.
I think they're extrapolating from there, figuring what the time would be, based on the accelaration of the top. Supposedly Steve Jones did this with his class and they came up with 6.6 seconds. To me, the big question is why they start the clock when they do, ignoring the fall of the east mechanical penthouse, which is a structure that covers an area the size of four apartment buildings on my block.

[Kent1]

I think they're extrapolating from there, figuring what the time would be, based on the accelaration of the top. Supposedly Steve Jones did this with his class and they came up with 6.6 seconds. To me, the big question is why they start the clock when they do, ignoring the fall of the east mechanical penthouse, which is a structure that covers an area the size of four apartment buildings on my block.

I've debated a few "scholars" on this. Few of them had read the WTC7 NIST report nor did they understand at all how or why the penthouse fell. They had no idea that it was caused by an internal collapse from the bottom that progressed upward. They seemed to think it was a separate small implosion that had no effect on the overall internal building structure.
Legge certainly made this mistake, so did Kuttler.

[tsig]

Cuddels, they topple buildings. Experts like Brent Blanchard and also Jowenko can tell you that, I will not post movies from it because you can find it if you want.

Huntsman, I rechecked and another expert Loizeaux, he says in fact:
The explosives are used as the catalyst and gravity is the engine.

Once it goes it goes, the tremendous amount of kinetic energy will break extremely strong structures. I was more referring to the initial moment, potential energy doesn't break the complete structure, it is the kinetic energy/momentum etc. Strictly speaking I was wrong that I said that the potential energy is only used to get the building down because once it is transformed to kinetic energy that is also used to break some other stuff.
And energy is energy isn't it. Let me correct that.

And in fact Greening already shows that once you only need a fraction of the kinetic energy (ok you are right: comes from the potential energy) to break the structure. The collapse time in the TT case differs only a little bit.

Let me end this posting by noting that for wtc7 both a controlled demolition and a structural failure are consistent with the laws of physics.
However if you know how difficult the technique is (there are only about 20 CD companies) to end with a pile of rubble then I'm more thinking about the first one.

I copy paste something from howstuffworks:

Blasters might also overestimate the amount of explosive power needed to break up the structure, and so produce a more powerful blast than is necessary. If they underestimate what explosive power is needed, or some of the explosives fail to ignite, the structure may not be completely demolished. In this case, the demolition crew brings in excavators and wrecking balls to finish the job. All of these mishaps are extremely rare in the demolition industry. Safety is a blaster's number-one concern, and, for the most part, they can predict very well what will happen in an implosion.

Planes hit the towers, 1/3 of the support beams were destroyed by the impact.
The load from gravity had to go to the remaining columns. Now the beams, already loaded beyond their design were heated and the heat reduced their ability to take the stress, when the force exceeded the design limit of one of the beams the others had to take the load since they were already at their limit the result was what you see.

[tsig]

So all those buildings that have been demolished over the years by collapsing them vertically so they don't damage anything nearby are in fact hoaxes on the part of the conspirators to make us believe that the twin towers could collapse the same way? Or are you just talking out of the wrong hole?

Planes hit the towers, 1/3 of the support beams were destroyed by the impact.
The load from gravity had to go to the remaining columns. Now the beams, already loaded beyond their design were heated and the heat reduced their ability to take the stress, when the force exceeded the design limit of one of the beams the others had to take the load since they were already at their limit the result was what you see.

[tsig]

Cuddels, they topple buildings. Experts like Brent Blanchard and also Jowenko can tell you that, I will not post movies from it because you can find it if you want.

Huntsman, I rechecked and another expert Loizeaux, he says in fact:
The explosives are used as the catalyst and gravity is the engine.

Once it goes it goes, the tremendous amount of kinetic energy will break extremely strong structures. I was more referring to the initial moment, potential energy doesn't break the complete structure, it is the kinetic energy/momentum etc. Strictly speaking I was wrong that I said that the potential energy is only used to get the building down because once it is transformed to kinetic energy that is also used to break some other stuff.
And energy is energy isn't it. Let me correct that.

And in fact Greening already shows that once you only need a fraction of the kinetic energy (ok you are right: comes from the potential energy) to break the structure. The collapse time in the TT case differs only a little bit.

Let me end this posting by noting that for wtc7 both a controlled demolition and a structural failure are consistent with the laws of physics.
However if you know how difficult the technique is (there are only about 20 CD companies) to end with a pile of rubble then I'm more thinking about the first one.

I copy paste something from howstuffworks:

Blasters might also overestimate the amount of explosive power needed to break up the structure, and so produce a more powerful blast than is necessary. If they underestimate what explosive power is needed, or some of the explosives fail to ignite, the structure may not be completely demolished. In this case, the demolition crew brings in excavators and wrecking balls to finish the job. All of these mishaps are extremely rare in the demolition industry. Safety is a blaster's number-one concern, and, for the most part, they can predict very well what will happen in an implosion.

Planes hit the towers, 1/3 of the support beams were destroyed by the impact.
The load from gravity had to go to the remaining columns. Now the beams, already loaded beyond their design were heated and the heat reduced their ability to take the stress, when the force exceeded the design limit of one of the beams the others had to take the load since they were already at their limit the result was what you see.

[tsig]

The free-fallers always seem to make the mistake of figuring if gravitational potential energy is used to accelerate something (conversion to kinetic energy), then there is no energy left for destroying it. It seems to me that, at least in the case of WTC7, they're overlooking the fact that all that kinetic energy, when it hits the ground, is spent breaking things up. So you can have both near free-fall speeds and energy to destroy the materials, just at different times.

Einsteen, since theinetic energy of the falling mass came to an end when it hit the ground, that energy gets used to destroy stuff. It's that simple in the case of WTC7.

Gravity provides all the energy needed.