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pomeroo
14th October 2007, 02:35 AM
I received the following sui generis e-mail from Morgan Reynolds. This comes after a typically deranged message from Ace Baker. Hmmm.

I have never heard from Reynolds before, and if loons don't want to see their nonsense posted on the JREF, then they damn well better not send it to me!


(Reynolds responds to Dr. Greening's new paper (the missing illustrations are--honest to God--outlines of Wile E. Coyote sumperimposed over the WTC)

Anyone, including Professor Greening, who wants to confine the issue of UA 175's "immaculate penetration" (with no collision/crash and virtually no deceleration, among other slick features) strictly to the empirical realm had best admit his/her contention that Newton's laws of mechanics are defunct. Honesty please. As I write in my preliminary remarks to NIST's denial of my Request for Correction, available here http://www.ocio.os.doc.gov/ITPolicyandPrograms/Information_Quality/PROD01_002619, on October 8, 2007:

I. NIST Versus Newton
Thousands of crashes and collisions have occurred daily throughout history. Crashes are mundane. The elementary physics of these interactions between objects have never been known to vary. All of them have obeyed the laws of physics. Yet somehow, 9/11 was mysteriously different, or so we are told. "Both the aircraft and the towers included deformable components and materials, whose interactions were properly accounted for in the models," states NIST on p. 3 of its response. "As a result, the aircraft would not be expected to decelerate immediately upon impact with the exterior wall of the tower." This is a breathtaking two-sentence sequence that I welcome.
‧ Deformation of materials requires energy.
‧ Energy can only be spent once.
‧ If energy is used to deform materials, it must come from somewhere.
‧ Energy used to deform materials is not available to maintain constant speed.
‧ Unless the flying object can find a new energy source, it must slow because energy consumed deforming materials is not available to keep speed constant.
Now let us repeat NIST's claim: "the aircraft would not be expected to decelerate immediately upon impact." Truly remarkable. In truth, NIST's modeling violates all three fundamental laws of Newtonian mechanics.
Under Newton's 1st law of motion, or law of inertia, if a plane does not decelerate upon impact with an exterior wall, no net force could have been impressed on the plane. To restate, if a plane continues to fly at the same speed, no force has been applied to it. That is the law of inertia. NIST's assertion that we would not expect the aircraft to "decelerate immediately upon impact" against a steel wall backed by steel/concrete floors apparently contradicts Newton's first law. Since a contradiction cannot exist in nature, I can think of six possible explanations:
(a) the 1st law never has been generally valid and/or does not apply to these kinds of interactions between bodies (Newton was wrong, for example, because the master scientist neglected to account for a time lag between impact and deceleration)
(b) the physical law has general validity, but was temporarily suspended in New York City between 8:46 and 9:03 a.m. on 9/11, perhaps by Muslim terrorists
(c) the twin towers and jetliners were built long after Sir Isaac Newton died and hence his old-fashioned laws could not be expected to apply to "biologically-inspired" designs over a quarter-mile tall and their interaction with jetliners
(d) pre-9/11 mechanics no longer apply in a post-9/11 world
(e) the law of inertia holds alright but the buildings were a figment of our imagination and there was no interaction between objects
(f) the law of inertia holds but the planes were a figment of our imagination and there was no interaction between objects (i.e., the plane was a video insert, a TV special effect).
Engineers would be shocked to learn that Newton's first law is invalid or did not apply on 9/11 or after 9/11. Their disbelief suggests that explanations a-d can be safely rejected because Newtonian mechanics still apply. And since the Twin Towers were real by all accounts, that leaves fake videos as the most likely explanation for observing little or no deceleration.
Under Newton's 2d law, sometimes called the law of acceleration, if a force is applied at the front of an airplane, it must slow and the back or tail of that aircraft must slow too. Unless that is, the front is no longer in the way of the back of the plane because the front is no longer connected to the rear, and the disconnect occurred without loss of kinetic energy. Further, according to the 2d law deceleration must be proportional to the force applied. The steel/concrete Twin Towers would administer quite a force against an aluminum airplane flying at high speed.
Since NIST insists that a 159-foot-long Boeing 767 disappeared into the north tower within 0.25 seconds and into the south tower within a corrected 0.23 seconds, almost the same as their speeds in the air, no force was impressed on these planes according to Newton's second law. ΣF = ma and if a = 0, then no net force was applied. When was Newton's 2nd law repealed? I did not get the memo. If the 2d law still applies, and I believe it does, then NIST cannot possibly be right and any gashes or hole in the towers that appeared at 8:46 a.m. and 9:03 a.m. on 9/11 must have been impressed by some method other than by a no-deceleration airplane. NIST apparently forgot the lecture on the first day in engineering mechanics class.
Newton's 3d law, sometimes called the law of reciprocal actions, states that all forces occur in pairs and these two forces are equal in magnitude and opposite in direction. That is, the forces of action and reaction between bodies in contact have the same magnitude, same line of action, and opposite sense. Therefore, if there is a force on the building in a crash, there is an equal and opposite force on the airplane.
If an aluminum plane ran into a Twin Tower, it must crumple, shatter and could not possibly leave a jetliner-shaped, cartoon-like "silhouette of passage" because in a collision with a tremendously strong building, arguably the strongest in the world, an airplane with its lesser mass, density and strength because it is built to be lightweight, would be far less able to withstand the equal force exerted on both bodies. Strength and massiveness matter greatly in which body will fare better in withstanding the equal force of an impact. Everybody knows this in shopping for a car: should I buy a heavy SUV for safety or accept the risk of driving a lightweight econobox or sportscar? If the damage inflicted on the other body in a collision between a jetliner and a Tower were likened to a sports contest, it would be something like Tower 100, Airplane 2. Imagine, for example, that a Tower fell on the airplane instead of the aluminum airplane hitting the Tower: complete and utter devastation of the airplane. However, this mismatch is not what the videos show. Instead, the aluminum plane cuts right through steel and disappears inside the Tower. This is impossible. Structural steel is far stronger than aluminum and present in abundant quantities, and would suffer only light damage compared to complete and utter destruction/rejection of an aluminum airplane, with most of its debris scattered outside the building, especially wings, tail section and a majority of the shattered fuselage. The five floors in each Tower allegedly impacted weighed more than 100X that of the alleged 140 ton airplanes. For more of this analysis, please see here (Madison ST911 Conference) or here (I Had a Car Crash, by Roadrunner - September 11, 2007).




ARA: http://drjudywood.com/articles/ARA/ARA.html
Appeal: http://drjudywood.com/pdf/070822_RFC_Appeal17a_JW.pdf
NIST RFC: http://drjudywood.com/articles/NIST/NIST_RFC.html
http://nomoregames.net/index.php?page=911&subpage1=nist_denies_prelim

My question to Professor Greening and other plane believers is, are the first three pages of statics textbooks null and void? What replaced them? If so, please direct me to the work proving the master scientist in error.

On the empirical contention that the ghost plane decelerated, please recall this careful analysis of the Fairbanks video that found virtually no deceleration:
http://nomoregames.net/index.php?page=911&subpage1=deceleration_WTC2_myers

I thank y'all, as we say in the charmed terrain I occupy, for your careful attention. Am I having fun? Funny you should ask. Am I being too elementary? Am I asking embarrassing questions at a seminar of worthies more learned than I? If so, I apologize. Presumably others have similar questions and they should be answered easily. True, I cling to the admittedly old-fashioned notion that fundamentals trump advanced work contrary to the fundamentals. Someone told me contradictions are impossible in reality. A is A. A is not B. The law of identity. I know, how pre-9/11.

Please, learned physical scientists, help me understand the demise of Sir Isaac Newton and where he went wrong on physical fundamentals.

Morgan Reynolds
Social Scientist
(Not a Physical Scientist)


PS I find this particular Greening assumption of interest: "The calculation of Te is straightforward because, to a very good approximation, the aircraft was moving on a trajectory that was perpendicular to the south face of WTC 2."

Oh yes, as does NIST, it was nearly a perpendicular while banking sharply left (according to videos) and striking at a 38 degree angle and "nearly missing the building," according to multiple accounts. Gee, what are the odds of a perpendicular hit (under these or nearly any conditions) and the wrecking ball, i.e., WTC 2, not striking the left wing/engine first and spinning that sorry aluminum structure counterclockwise off to the east, ripping its tail section off and flinging it blocks away, among other catastrophic effects? Oh no, we are to believe that most of the 3.1 million pieces and contents of the aluminum can disappeared inside the tower. Aside, that is, from a few impossibly placed pieces of "evidence." Rather small chance you say? The four cleanest crash sites in aviation history, all within 77 minutes, my, my. Like no other "crashes" ever or since in aviation history. The Respectable Media and "my" government told me so, backed up by prominent physical scientists like those on this list. After all, each and every such scientist is an independent voice, not a poodle of the Feds. Uh huh. Oh yeah. Economists have repeatedly shown that scientists, like other "agents," do not respond predictably to material incentives. Ok, must all be true then.

Not true to me though. The anti-Newton revolution, trashing basic physics, should be documented. Please inform me and the rest of the great unwashed where to look for your proofs Newton erred. Thank you.

pomeroo
14th October 2007, 03:02 AM
What I find really extraordinary that we have here a rare instance of a total loon making highly specific claims. He is not babbling the usual vague, mystical codswallop. He is making claims that can be demonstrated to be wrong-headed. I am curious to see how he responds to the inevitable refutations.

Incidentally, please--please!--click on the link Reynolds provides. Judy Wood's correspondence with NIST is priceless.

gumboot
14th October 2007, 03:40 AM
The contentions of the "plane does not decelerate" no-planers are based entirely on a pixel-by-pixel analysis of video depicting the impact of UA175.

The problem with their interpretation is not so much that their process is flawed. The problem is they do not allow for sufficient margin of error.

The most accurate unit of measure they have is 1 pixel. However as I have discussed previously with Ace Baker, a single pixel, in the context of these videos, has an enormous margin of error - ample to render their "no deceleration" calculations meaningless.

All of their calculations and science are meaningless, because they are all build on the single premise that UA175 did not decelerate upon impact with WTC2. There is simply no way for them to establish this premise.

-Gumboot

Nick227
14th October 2007, 04:00 AM
Morgan,

I'm a die-hard CTist myself, and I do sympathise with your desire to rekindle the public debate on 9/11. However, even to me, as similarly a non-scientist, this first part is just a little mad....

Thousands of crashes and collisions have occurred daily throughout history. Crashes are mundane. The elementary physics of these interactions between objects have never been known to vary. All of them have obeyed the laws of physics. Yet somehow, 9/11 was mysteriously different, or so we are told. "Both the aircraft and the towers included deformable components and materials, whose interactions were properly accounted for in the models," states NIST on p. 3 of its response. "As a result, the aircraft would not be expected to decelerate immediately upon impact with the exterior wall of the tower." This is a breathtaking two-sentence sequence that I welcome.

I rather doubt that the NIST report is suggesting that no deceleration took place. That is demonstrably nonsense. It seems to me to be saying that the pattern of the crash is consistent with these planes hitting these buidings.

You're creating an argument from your own misunderstanding. Please stop because this doesn't serve anyone.

Nick

Blackadder_no
14th October 2007, 04:26 AM
What's with all the claims that the Twin Towers (and WTC7 for that matter) were the "strongest buildings in the world"? Whenever I hear that phrase, I keep picturing something bunker-like, not the spindly metal construction of a skyscraper.

Btw, I seem to remember that Newton's laws applied to rigid bodies, as in "not deforming"...

WilliamSeger
14th October 2007, 05:01 AM
Morgan Reynolds responds to... who? Greening? I don't see any response at all to what I took as Greening's main point: "Reynold’s argument that the Boeing 767 showed no deceleration after striking WTC 2 is also demonstrated to be invalid using video evidence showing that the aircraft’s velocity was significantly reduced during the initial stages of the impact."

T.A.M.
14th October 2007, 07:35 AM
Morgan,

I'm a die-hard CTist myself, and I do sympathise with your desire to rekindle the public debate on 9/11...Nick

derail:
Funny Nick, i figured you for an "undecided", or a t most a "moderate "CTist". You do not strike me as a "Die Hard" especially on "9/11"

TAM:)

T.A.M.
14th October 2007, 07:40 AM
ummm...isnt Reynolds reply aimed at NIST? Where in his "reply to Greening" doe he actually "reply to Greening"?

TAM:)

chillzero
14th October 2007, 08:04 AM
Thread closed pending review

Thread reviewed and re-opened.

pomeroo
15th October 2007, 05:11 AM
Morgan Reynolds has called us out. I cautioned him that many regulars with strong technical backgrounds have worn this topic to rags in innumerable brawls with Ace Baker. Here is his challenge to Debunking Central:

Morgan Reynolds wrote:


Cat got your tongue? I'm not easily diverted by your repeated failures to address Professor Newton. I can understand high school physics and their application to crashes. Can you? Your avoidance of the issue and resort to authority suggest not.
How dense are you and your friends on the forum? The question may answer itself.
My statements on the fake planes include the following:
http://nomoregames.net/index.php?page=911&subpage1=nist_denies_prelim
http://nomoregames.net/index.php?page=911&subpage1=had_a_car_crash
http://nomoregames.net/presentations/Madison_No_Planes_Final_August_07.ppt.htm
http://nomoregames.net/index.php?page=911&subpage1=exploding_the_airliner_crash_myth
http://nomoregames.net/index.php?page=911&subpage1=deceleration_WTC2_myers
http://nomoregames.net/index.php?page=911&subpage1=plane_trick_wtc2
http://nomoregames.net/index.php?page=911&subpage1=no_planer_resigns
http://nomoregames.net/index.php?page=911&subpage1=we_have_holes
I'd be delighted to learn what is wrong within them.

Until you and your buds address Newtonian mechanics, spare me your missives. On videos, Joe Keith says it all in this recent email to me:



(For some reason, I can't post the last part of Reynolds's message. I will post it separately.)

pomeroo
15th October 2007, 05:16 AM
Keith says it all in this recent email to me:

If anyone runs any DVD of the WTC south tower airliner crash and pauses the DVD when the airliner initially comes into view, and places a mark at the point of the airliner's nose, and then counts the number of single steps (frames) it takes for the airliner to fly its total length (until the tail passes the mark), and then single steps to where the airliner first touches the tower, and then counts the single steps until the airliner is totally absorbed into the tower, he will find, since the number of steps is the same, that the airliner flies through thin air at the same speed that it flies through a steel and concrete tower. Impossible!! And, if you concentrate on each frame as the airliner morphs into the steel and concrete tower, you will see no crunching of the airframe, no breaking off of parts, no wings bending or breaking off, no reactions as engines hit points of resistance; absolutely no sign of a crash. The videos are irrefutably fake!! And, this is not the only way we 'no planers' have proven the videos to be fake, albeit the easiest; we have graphic arts experts who have proven it in the most scientific ways.

DGM
15th October 2007, 05:20 AM
Morgan Reynolds has called us out. I cautioned him that many regulars with strong technical backgrounds have worn this topic to rags in innumerable brawls with Ace Baker. Here is his challenge to Debunking Central:

Morgan Reynolds wrote:


Cat got your tongue? I'm not easily diverted by your repeated failures to address Professor Newton. I can understand high school physics and their application to crashes. Can you? Your avoidance of the issue and resort to authority suggest not.
How dense are you and your friends on the forum? The question may answer itself.
My statements on the fake planes include the following:
http://nomoregames.net/index.php?page=911&subpage1=nist_denies_prelim
http://nomoregames.net/index.php?page=911&subpage1=had_a_car_crash
http://nomoregames.net/presentations/Madison_No_Planes_Final_August_07.ppt.htm
http://nomoregames.net/index.php?page=911&subpage1=exploding_the_airliner_crash_myth
http://nomoregames.net/index.php?page=911&subpage1=deceleration_WTC2_myers
http://nomoregames.net/index.php?page=911&subpage1=plane_trick_wtc2
http://nomoregames.net/index.php?page=911&subpage1=no_planer_resigns
http://nomoregames.net/index.php?page=911&subpage1=we_have_holes
I'd be delighted to learn what is wrong within them.

Until you and your buds address Newtonian mechanics, spare me your missives. On videos, Joe Keith says it all in this recent email to me:
Keith says it all in this recent email to me:


(For some reason, I can't post the last part of Reynolds's message. I will post it separately.)
Here's my response to no planers........................................... ..

Hyperviolet
15th October 2007, 05:46 AM
Morgan Reynolds and his associate, Judy Wood, are a pair of lunatics.
No planes? Space Weapons?
What's next? JFK did 9/11?

I say leave him in isolation, he is in no danger of converting anyone.

CHF
15th October 2007, 06:31 AM
I see no point in arguing with what twoofers call a "disinfo" agent.

Anti-sophist
15th October 2007, 07:32 AM
Have you asked him, or Ace Baker, to measure the deceleration of the F4 in the Sandia test? The way I read this silly argument, this video must also be fake:

http://www.youtube.com/watch?v=TVz5vhNvskk

Or will they go the Killtown route and claim that particular video is also part of the PSYOPS!

The argument that the back of a plane should appreciably decelerate as the front of the plane hits something is beyond absurd. There is no violation of Newton's Laws, either, if you properly invoke them.

Arkan_Wolfshade
15th October 2007, 10:08 AM
Morgan Reynolds has called us out. I cautioned him that many regulars with strong technical backgrounds have worn this topic to rags in innumerable brawls with Ace Baker. Here is his challenge to Debunking Central:

Morgan Reynolds wrote:


Cat got your tongue? I'm not easily diverted by your repeated failures to address Professor Newton. I can understand high school physics and their application to crashes. Can you? Your avoidance of the issue and resort to authority suggest not.
How dense are you and your friends on the forum? The question may answer itself.
My statements on the fake planes include the following:
http://nomoregames.net/index.php?page=911&subpage1=nist_denies_prelim
http://nomoregames.net/index.php?page=911&subpage1=had_a_car_crash
http://nomoregames.net/presentations/Madison_No_Planes_Final_August_07.ppt.htm
http://nomoregames.net/index.php?page=911&subpage1=exploding_the_airliner_crash_myth
http://nomoregames.net/index.php?page=911&subpage1=deceleration_WTC2_myers
http://nomoregames.net/index.php?page=911&subpage1=plane_trick_wtc2
http://nomoregames.net/index.php?page=911&subpage1=no_planer_resigns
http://nomoregames.net/index.php?page=911&subpage1=we_have_holes
I'd be delighted to learn what is wrong within them.

Until you and your buds address Newtonian mechanics, spare me your missives. On videos, Joe Keith says it all in this recent email to me:



(For some reason, I can't post the last part of Reynolds's message. I will post it separately.)
http://img384.imageshack.us/img384/3005/sciencenh7.jpg

I'll try to put something more thorough together later.

Alferd_Packer
15th October 2007, 10:17 AM
I wonder if Morgan Reynolds has ever heard of using water jets to cut steel?

How can water, which isn’t even a solid (thus it is obviously much “softer” than steel) cut through steel?

R.Mackey
15th October 2007, 10:32 AM
I'm sure somebody has already thought of this, but --

We're talking about a 767, which is roughly 45.5 meters long, right?

In the case of WTC 2, the vehicle was travelling at approximately 245 meters per second. Neglecting deceleration for a moment, the aircraft would totally disappear from view in (45.5 m / 245 m/s) = 0.18 seconds. Assuming 30 frames per second, this is at most five and a half frames of video.

You cannot estimate a deceleration with less than three frames -- difference between frame 1 and 2 gives you baseline velocity, difference between 2 and 3 gives you new velocity, and difference between the two measurements gives you instantaneous deceleration. At most we have two or three frames extra -- and zero frames extra if we assume the endframes are mixed state, i.e. capture the aircraft somewhere between flying and impacting, which will contaminate our results.

If Dr. Reynolds is starting his analysis with the frame after contact, it may be that the majority of deceleration has already occured. There will be a big impulse at the perimeter columns, plausibly destroyed in the very first frame, and damaging the aircraft which reduces its ability to transmit force to the tail. By restricting himself to these and only these frames, he may well have already missed a good chunk of deceleration.

A more thorough analysis will quantify the error in measurement, but it already appears to be unacceptably large. We're trying to fit a second-degree polynomial (a parabola, representing a constant deceleration of a moving body) to at most five and plausibly fewer data points. This is called an "overfit." We just don't have enough data.

Assuming we buy his ridiculous argument, what does he think hit the WTC? Apparently nothing -- he is arguing that the impacting object is immune to Newton's Second and Third Laws, and as far as we know, there is no object that meets those specifications. If nothing hit the Towers, what made the hole? What made them sway? What did everyone see?

Why do we bother with such idiocy?

Alareth
15th October 2007, 10:33 AM
I wonder if Morgan Reynolds has ever heard of using water jets to cut steel?

How can water, which isn’t even a solid (thus it is obviously much “softer” than steel) cut through steel?

Planes are made from metal, which is heavier than air so how can they fly?

The evil conspiracy has its roots dating back over a hundred years when those NWO shills Orville and Wilbur Wright first tricked the sheeple into believing such things as planes could actually exist.

Dave Rogers
15th October 2007, 10:48 AM
You cannot estimate a deceleration with less than three frames -- difference between frame 1 and 2 gives you baseline velocity, difference between 2 and 3 gives you new velocity, and difference between the two measurements gives you instantaneous deceleration. At most we have two or three frames extra -- and zero frames extra if we assume the endframes are mixed state, i.e. capture the aircraft somewhere between flying and impacting, which will contaminate our results.

However, with the flight 175 video we do have sufficient frames before impact that the velocity immediately before the impact is well known. What the analysis should therefore do is determine the (probably roughly constant) velocity in a sufficient number of frames prior to the impact, then look for deviations from the straight line of position against time in frames from the first after the nose strikes to the last before the tail vanishes. However, as I learned to the cost of a small part of my sanity in the Ace Baker "Pinnochio's Nose" debacle, the errors in the position of the airplane are actually quite significant and visible on a plot of position against time (or at least they are on a plot of velocity against frame number), so I suspect that any actual deceleration is quite easily lost in the noise. I'm happy not to bother investigating that suspicion any further, having already experienced the futility of arguing with those who are demonstrably disconnected from reality.

Dave

R.Mackey
15th October 2007, 10:55 AM
However, with the flight 175 video we do have sufficient frames before impact that the velocity immediately before the impact is well known. What the analysis should therefore do is determine the (probably roughly constant) velocity in a sufficient number of frames prior to the impact, then look for deviations from the straight line of position against time in frames from the first after the nose strikes to the last before the tail vanishes.

Agree -- I was criticizing Reynolds' stated method, not saying it was totally impossible. In any case, while you may reduce the error in initial velocity (thus eliminating one of the three parameters in our second-degree polynomial fit), you are still forced to fit the remaining two with at most five and probably fewer data points. This is not as bad, but still unpromising.


However, as I learned to the cost of a small part of my sanity in the Ace Baker "Pinnochio's Nose" debacle, the errors in the position of the airplane are actually quite significant and visible on a plot of position against time (or at least they are on a plot of velocity against frame number), so I suspect that any actual deceleration is quite easily lost in the noise. I'm happy not to bother investigating that suspicion any further, having already experienced the futility of arguing with those who are demonstrably disconnected from reality.


Yes, I remember that debacle.

Just for fun, we could propagate those position errors through the fit. I imagine our error estimate would land somewhere in the 100 m/s2 range, or +/- 10 G's by the time we were done...

dudalb
15th October 2007, 11:11 AM
?

Why do we bother with such idiocy?

I feel your pain,but in a world where a proven fraud like Uri Geller can get a big network reality show (On NBC,And Johnny Carson,who exposed Geller are a phony on his show,is turning over in his grave),it's a sad fact that there is no Woo to silly not to find a following,and it has to be fought constanly.

tacodaemon
15th October 2007, 11:34 AM
I rather doubt that the NIST report is suggesting that no deceleration took place. That is demonstrably nonsense. It seems to me to be saying that the pattern of the crash is consistent with these planes hitting these buidings.


I interpreted it as meaning that the aircraft wouldn't decelerate to zero instantaneously (like the "it shoulda bounced off!" no-planers apparently expect). If Reynolds is basing this entire long-winded argument on a nitpicking reading of a single (admittedly somewhat vaguely written) sentence, well.

rwguinn
15th October 2007, 12:08 PM
Agree -- I was criticizing Reynolds' stated method, not saying it was totally impossible. In any case, while you may reduce the error in initial velocity (thus eliminating one of the three parameters in our second-degree polynomial fit), you are still forced to fit the remaining two with at most five and probably fewer data points. This is not as bad, but still unpromising.



Yes, I remember that debacle.

Just for fun, we could propagate those position errors through the fit. I imagine our error estimate would land somewhere in the 100 m/s2 range, or +/- 10 G's by the time we were done...

HEy!
Our old friend Apollo20 Thinks he can measure acceleration from that film... And ignore the fact that it was a non-solid structure, too!
A cursory survey of available information on the impact of Flight 175 on WTC 2 shows at least two instances of measurable velocity reductions: one derived from the much-discussed Evan Fairbanks video footage, and the other based on a video analysis reported by Y. Omika et al. in the January 2005 issue of the Journal of Structural Engineering. Thus the Evan Fairbanks video, when viewed as still frames ~ 0.03 seconds apart, shows a measurable velocity reduction of the tail end of the aircraft, (of about 5 m/s), when the nose of the 767 had penetrated about 16 meters into WTC 2. This increases to a velocity reduction of about 30 m/s, or 12 % of the initial impact velocity, approximately 0.15 seconds into the impact. By comparison, Omika et al. use the analysis of an unnamed video to estimate a 50 m/s velocity reduction of the aircraft after 0.15 seconds, increasing to a 100 m/s reduction after 0.2 seconds (http://forums.randi.org/showthread.php?t=95876).

R.Mackey
15th October 2007, 12:13 PM
Well, since we have two estimates, one of 30 m/s at 0.15 seconds and one at 50 m/s at 0.15 seconds, this suggests an error (maximum) of +/- 20 m/s per 0.15 seconds, or +/- 133 m/s2. If we assume the error is correlated and add in quadrature, we get +/- 94 m/s2.

Compares very well to my 10 G's estimate above. Damn I'm good. :D





ETA: For those with no grouding in science -- or no sense of humor -- that's actually not a joke. The above figure of 94 m/s2 is what you get if you divide the standard deviation by delta-T of 0.15 seconds. The correct answer is [(10 m/s)2 + (10 m/s)2 / (2 - 1) ]1/2 divided by 0.15 seconds, or about 94 m/s2, i.e. 9.4 G's of uncertainty. I.e. an awful lot.

It isn't totally clear if acceleration (true rate of change of velocity) or impulse (i.e. aggregate delta-V) is more appropriate for this calculation, given the relatively short duration of the phenomenon. Dr. Greening's choice of impulse is certainly arguable. In this case, instead of finding the error in acceleration, we can use error in velocity, which is +/- 14 m/s, i.e. don't divide by delta-T.

This is still an awful lot of error -- we can refigure the calculation in terms of force by F delta T = m delta V, where m is the mass of the aircraft. This instead gives us an uncertainty in force of 9.4 MN over the duration.

Bottom line, the error is huge, and Reynolds is out to lunch claiming there's "no change."

rwguinn
15th October 2007, 12:32 PM
Well, since we have two estimates, one of 30 m/s at 0.15 seconds and one at 50 m/s at 0.15 seconds, this suggests an error (maximum) of +/- 20 m/s per 0.15 seconds, or +/- 133 m/s2. If we assume the error is correlated and add in quadrature, we get +/- 94 m/s2.

Compares very well to my 10 G's estimate above. Damn I'm good. :D


<.....snip>>
IYes. Yes, you are...
Just pointing out that the desire to find fault can override any scientific training and critical thinking--
for anyone of us and/or them...

R.Mackey
15th October 2007, 12:43 PM
I am cheating a little bit, though.

If we accept those two measurements, this suggests the true change in velocity at impact + 0.15 seconds is equal to roughly 40 m/s +/- 14 m/s. The error is large, but the fractional error is not so large as to be useless. For the actual result to be 0 m/s, which is what Reynolds claims, we have to be 40/14 = 2.86 standard deviations away from the true value, i.e. we can claim there is at least some deceleration with roughly 97% certainty.

It still might be fun to start with the position errors and propagate it to see if we get agreement, but this is good enough.

Reynolds is wrong.