Downward Acceleration of the North Tower

http://www.youtube.com/watch?v=xG2y50Wyys4

The roofline of WTC1 (The North Tower) begins dropping with sudden onset and accelerates uniformly downward at about 64% of the acceleration of gravity (g) until it disappears into the dust. This means it is meeting resistance equal to about 36% of its weight. The implication of this, however, is that the force it is exerting on the lower section of the building is also only 36% of the weight of the falling section. This is much less than the force it would exert if it were at rest. The acceleration data thus prove that the falling top section of the building cannot be responsible for the destruction of the lower section of the building.

[I want to acknowledge the work of Graeme MacQueen and Tony Szamboti who have been engaged in similar measurements by other means and have reached similar conclusions.]

--David Chandler, AE911Truth

I know it is obvious to you David, but

I know it is more than obvious to you David, but I think it would be helpful to account for the 36% being what is left after you subract, 64% from 100%. People who are not familiar with the concept of the acceleration of gravity need to be walked through this step by step.

Thank you for all your work.

Show "Mr. Chandler, You say you" by haverman

Simplifying Assumptions

The first step in almost any physics calculation is to make simplifying assumptions. Regardless of the internal structure of the building, the top section can in fact, for the purpose of this analysis, be considered to be a block. What I am sayins is EVEN IF it were a solid, monolithic block, the fact that it accelerates downward uniformly proves that the force of interaction with the lower section of the building is less than its weight. Notice I have not mentioned explosives in this argument (or in this video) at all. However the point here is that even with these gross simplifying assumptions, the top section of the building cannot be what is destroying the bottom section. Any inferences about what is in fact destroying the bottom section of the building is left to the reader's (viewer's) imagination.

I agree, by the way that taking the block concept literally is a mistake. There is not even a mechanism for the top section of the building to exert a downward force on the supporting columns below the break. Others have made this point. Still the observation in this video is a reasonable contribution to the discussion.

Please help me understand the statement "there is not even ...

I don't understand the statement: "There is not even a mechanism for the top section of the building to exert a downward force on the supporting columns below the break."

Isn't the top exerting a downward force equal to 36% of its potential energy? I realize that this 36% is insufficient to crush the lower, stronger and heavier intact structure below the break.

Is the "lack of a mechanism" due to the fact that the supporting columns are vertical and therefore have very little surface area presenting in a horizontal plane so that almost all of the weight of collapsing floors would hit lower floors which do present a horizontal plane?

Or is the "lack of a mechanism" due to some other principle?

I find it amazing that there are not 50 or more "replys" to this video. I can't understand the blindness to - or indiffence to - the basic physics. I wonder what Shyam and John would say in answer to this.

Still hoping someone knowledgeable will explain above question

"I don't understand the statement: "There is not even a mechanism for the top section of the building to exert a downward force on the supporting columns below the break."

This is really interesting. I am still hoping someone knowledgeable will explain it.

There was no impact

What Dave meant by the sentence you are quoting is that without impact there is no mechanism to generate a sufficient force to collapse the building below.

The only way a sufficient force could have been generated was for there to have been impact, which can produce an amplified load. However, that requires significant deceleration. There is no deceleration observed as the upper block is in constant acceleration for the entire 32 meter (105 feet) or 8 story measurement range that Dave measured the fall over.

"There is not even a mechanism..."

(responding to zmzmzm)
> I don't understand the statement: "There is not even a mechanism for the top section of the building to exert a downward force on
> the supporting columns below the break."

I'm referring to the fact, pointed out by someone else (I can't find the reference right now...help?) that there is no "hammer head" surface at the bottom of the top "block". It is a bunch of "spear-like" vertical columns that would inevitably miss their corresponding columns below and simply penetrate the floor members. Therefore there is no mechanism to deliver a blow to the standing columns.

(By the way, the reason I have not been active in this discussion is I have a full-time "day job" teaching. The first couple times I checked there were hardly any responses, so I didn't check back until tonight and saw a whole bunch. I'm not trying to avoid the discussion.)

Perhaps you are referring to Graeme MacQueen

David:

First of all, thank you for responding.

I recall having seen a video by Graeme MacQueen in which he explained that "there was no pile driver." (And thank you for the "spear-like" analogy)

What follows below is my response to a friend to whom I sent your latest video. I am posting this in the hopes that it might contribute something useful.

My friend wrote:

" I don’t understand the argument in the video. Is it that there was no energy available to collapse the building since the top kept accelerating for the entire time of the collapse? I’m not sure how the video would prove this since it only shows the first few seconds of the collapse. Please comment."

I responded:

My first comment is that you watch the video again. My second comment is that you watch the video with a colleague who has a strong background in physics. Better yet - watch it with two or three friends or colleagues who have an interest in physics or mechanics or engineering or math or any related field.

As you have correctly noted, much of the online discussions are polluted with ad hominem attacks and name calling and ludicrous non-sequitors like (I don't believe in conspiracy theories -- or -- I don't believe in flying saucers ---- or --- I don't believe in chemtrails --- or I don't believe in crop circles).

Obviously, none of the above has any bearing whatsoever on the physics of what happened on 911 to any of the buildings that were destroyed or badly damaged.
These buildings include WTC 1,2,5,6 and 7 (I don't know anything off the top of my head about 3 and 4 - but I assume they were at minimum damaged.) And also included in damaged buildings is the Pentagon.

Getting back to the video:

I think that David Chandler, a high school physics teacher, is far more capable of making his own arguments than am I - but nevertheless, I will do my best to comment as you have requested. (I am not suggesting that because he is a physics teacher, that he is necessarily correct. Professionals in every disciple make mistakes all the time. Sometimes the mistakes are honest, and sometimes the "mistakes" are not "mistakes" at all but deliberate attempts to deceive).

Okay - so much for philosophy:

The essential argument put forth in this video - as I understand it - is that the acceleration of gravity is eating up 64% of the available gravitational energy of the mass of the top - leaving only 36% of its mass available for downward force against a resistance.

There are several other aspects observable in the video, but I think the main point Chandler was addressing in this video is the one above.

I would add, that NIST has put forth NO EXPLANATION AT ALL for the collapse mechanism of WTC 1 and 2. What they have done is put out a report that ends at "the initiation of collapse." A report that ends with the initiation of collapse has ended at the beginning.

Can you direct me to a NIST report of the actual collapse mechanism, after the point of initiation?

To give you an analogy (which I know you dislike):

A boxer lands a punch to his opponent's head. His opponent falls down and lies motionless on the mat. The ref counts to 10, and the fight is over. The medics come out with a stretcher and carry the motionless fighter away.

An explanation that only goes as far as the initiating event tells us that the "winner" landed a punch to the loser's head. Then it just leaves us to conclude that the guy was knocked out.

BUT there are many other possibilities. Only a skillful and honest medical examination can tell us what happened after the punch landed.

After all - boxers are continuously landing punches to one another's heads. Some of these punches seem to have no effect at all. Some stagger the opponent momentarily and he quickly recovers. Some stagger him so badly that he remains standing but the ref stops the fight because he is no longer able to defend himself adequately. Some knock him down and he remains conscious but doesn't have the will, or co-ordination to get up. Some knock him out cold. Some kill him.

Anyway - we can't "conclude" that he was knocked out, just because his opponent landed a punch to his head and he fell down, remained motionless and was carried off in a stretcher. We need a competent medical examination to establish what actually happened to him.

Possibilities include:

1: He was knocked out cold.

2: He fell down and stayed down for any number of other reasons:

A: He was bribed

B: He was threatened

C: He was tired of getting punched

D: It occurred to him as he was lying there, that he would much rather be a veterinarian, and if got up he might suffer brain damage as the other guy was beating the shit out of him. He decided to fake total unconsciousness so as not to be labeled a coward.

E: Any number of other possibilities.

A skilled medical team might or might not be able to establish the actual "collapse mechanism." If there were good videos from a number of angles, it might be possible by observing his eyes, his eyelids, his knees, the changes in color of his skin, the speed of his respiration, the relationship in time between the landing of the punch and the responses of his body -- to establish the "collapse mechanism."

A good video analysis of the punch, might show the velocity of the impact - whether or not the punch was actually pulled by his opponent, or whether the punch was accelerating with increasing force etc. etc. The possibilities are endless ---especially as a whole lot of money changed hands as a result of the fight.

Anyway - my point is - that to say "his opponent landed a punch to his head and it therefore follows that this punch knocked him out" is not science - it is rhetoric.

Thank you for replying so dispassionately

" However the point here is that even with these gross simplifying assumptions, the top section of the building cannot be what is destroying the bottom section. "

I am very glad we can agree on this point. The top section isn't what is destroying it. The falling floors are. It's hard to know exactly how it starts, but the tower(s) disintegrate because the floors are ripped off by floors from above being driven down by gravity. Then the outer columns briefly stand and and mostly keel over outwards. As some of these sections are quite tall, they hit other buildings hundreds of feet away. No mystery there. And the fact that both towers fall in identical ways is to my mind very very strong evidence that it's a process of disintegration unique to them and the way they're put together. The way they're puit together and defy gravity determines how they come apart.because of gravity. To me, that's logical.

When you, Mr Chandler, observe that the lower section is coming apart as the result of something other than the downward force of the top section, I agree completely : there are in fact multiple processes of destruction going on : 1) the floors pancaking 2) as a result : the outer columns losing connection to the floors and falling outward and 3 ) the central columns falling, but only completely after the floors have raced past and ripped loose. Of all 3 elements, the central columns have the most independent strength. i.e. can hang on longer that the other two. And that''s exactly what I see happening. There was new footage of tower 1 recently that shows the central columns ( partly ) surviving , even after the whole thing has come crashing down around them.

I have a strong sense of being right about this, but meet with very little openmindedness here. ( minus 12 points! )
I really believe that like the grassy knoll shooter, the controlled demolition hypothesis will NEVER be the thing that suddenly breaks the case wide open. Look elsewhere for signs of conspiracy. They do exist I believe. But not in the billowing dust clouds of towers 1 and 2.

Dodging and Weaving

> I am very glad we can agree on this point. The top section isn't what is destroying it. The falling floors are.

Due to problems with the pancake theory, NIST dropped that theory and adopted the pile driver theory. Now since there is a problem with the pile driver, you are going back to pancakes. This feels like you're dodging and weaving, to continue the boxer analogy found elsewhere in this thread. My current analysis is focused on the pile driver theory, and I think it discredits it. Let's just leave it there for that discussion, unless you think I'm wrong. If you want to revive the pancake theory (without NIST's backing), that is a separate discussion.

>>not from some magical

>>not from some magical sequence of well-times explosive blasts

It's been fascinating to me how the debunkers have been basically stumped into talking about nonsense, baseless claims and meaningless details by David's work, a testament to the power of it.

Thanks!

More validation from their efforts

It's also noteworthy that they make such efforts, rather than simply saying 'Oh what you're suggesting is ridiculous'. I guess David is a tougher target than the average talkshow host.

Show "then get specific about the demolition part of your hypothesis" by haverman

please go to EXACTLY 2:49 in the video

At exactly 2:49 in the video, a HUGE beam is thrown to the right. Although I cannot see the roofline, the beam seems to me to be SIGNIFICANTLY HIGHER than the roofline, judging by the plumes of dust cloud. In fact it looks to me, like that beam is WAY WAY higher than the disappearing roofline.

First of all, do you agree that that beam is SIGNIFICANTLY higher than the roofline? If so, is there any way that a gravitational collapse accelerating downward could sever a beam and then throw that beam so far upward? (without the help of an additional energy source).

Playing devil's advocate, I am picturing the acrobatic act whereby one person jumps off a ladder onto one end of a see-saw - and that throws the person who is standing on the other end of the see-saw upward. BUT if the entire stage upon which the act was being performed was falling downward - then the person who was being thrown upward, relative to the see-saw would still be falling downward relative to a fixed outside point.

Anyway, my question for David is, "Is that HUGE beam being thrown to the right (and to my observation upward) significant?"

Thank you.

Constant acceleration - absence of 'transition'

There appears to be a few seconds of collapse of the upper section (from the roof-line to the reference point beneath the fire) before the lower section (beneath the fire) startes to collapse.

It's interesting that the vertical acceleration of the roofline when it is collapsing into its own upper section is indistinguishable from the acceleration during and after the collapse initiation of the lower section.

That is all the more astonishing, given as you mention, that the upper section began to pulverise and much of its mass was lost.

Thanks for all of your contributions.

Complete Refutation of the OCT yet so few comments - why?

Interesting observations speakingup.

What I can't understand is why this video, which is a Complete Refutation of the OTC is not getting a whole slew of comments.

The physics is fascinating and almost no one seems to be interested in discussing it.

It seems that I am alone in wondering how that HUGE beam got thrown so far above the collapsing roofline. (see one of my posts above).

Simplest is best...

I agree that David Chandler's work clearly illustrates the proposterous nature of the official story.... I think that material like this will create the tipping point of public opinion.

I checked out the aspect you mention and I must admit that I think it shows the toppling of a standing body (maybe a beam at the corner of the building), rather than the explosive projection of a beam.... but I may be wrong...

the beam

The beam I am referring to is WAY in the air to the right of the dust cloud and clearly visible against the blue sky. It falls down near the right edge of the video. It is seen ejecting at 2:49. By 2:51 is it right above the "ub" in YouTube in the lower right hand corner. Maybe it's easiest to pause at 2:51 and locate the beam, and then back up to 2:46 and watch it a few times.

flying not toppling

Yes, I see what you mean....it has been vigorously ejected for sure.

I was focusing on the upright body which emerges from the dust cloud and topples at around the same time.

Does it look to you like it is HIGHER than the roofline?

It looks to me like it is considerably higher than the falling roofline which is hidden behind the dust clouds. I can only guess where the roofline is by the plumes. Maybe David can draw a horizontal line from the roofline to that beam. It seems to me that once it was ejected, it would be falling at 100% freefall (minus a little air resistance) and of necessity be quite a bit BELOW the falling roofline which was only falling at 64% of freefall. (The lateral component of the ejection has no bearing on the downward gravitational force.)

So how did that huge beam manage to get up there in the air so high above the roofline? It seems to me (if my observation is correct and that it is higher than the roofline) then there had to be a powerful force throwing it UPWARD. I can't imagine any interaction of falling beams that would account for that beam being where it is in a gravitational collapse. Can you?

I wish David would weigh in on this. I don't want to seem like a broken record but that looks to me like a very hefty beam and it looks to me like it is WAY above the roofline.

flying beam

its flight does appear to follow an arc ... up and out..

really good observations

All your observations are really interesting.

I agree that "There appears to be a few seconds of collapse of the upper section (from the roof-line to the reference point beneath the fire) before the lower section (beneath the fire) startes to collapse."

I would add that these few seconds correspond to a pretty hefty chunk of the upper "block" disappearing. Where could these disappearing floors have gone? They haven't yet collapsed the floors below the fire line, so I would reason that a percentage of their mass is sitting on top of the intact structure, and a percentage of their mass is outside the building having been ejected as solid beams and pulverized everything else. I have no way of guessing what the percentage breakdown would be, but obviously the "upper chunk" has lost a good deal of weight.

Your second two observations are really interesting also.

I hope David or someone else at AE911 keeps monitoring these posts - because there are some really good points made (like the ones you have made in your post above) that might be worth expanding on. One never knows what particular way of explaining things or pointing things out, turns the magic key and makes the light go on for different individuals.

"indistinguishable..."

>"It's interesting that the vertical acceleration of the roofline when it is collapsing into its own upper section is indistinguishable from
> the acceleration during and after the collapse initiation of the lower section."

Excellent point! It seems there is no coupling between the movement of the roofline and the collapse mechanism below.

YouTube Comments turned off

The comments seem to have been turned off for AE's videos.

Once again....

comments have been disabled for this video on youtube. WTF!?

Who decides if comments should be disabled?

... Youtube or the person who posts the video?

the person who posts decides

I asked this question of AE911Truth and they replied that it is the poster who chooses to disable comments and that these videos were getting "spammed" and so the poster (AE911truth) decided to disable text comments but allow video comments.

Yes, a strategy to discredit

Yes, a strategy to discredit or distract from strong presentations is to make every effort to link it to garbage or negative comments. A good choice on his part it seems.

Comments are now enabled in copy posted by someone else

Comments are now enabled in copy posted by someone else:

http://www.youtube.com/watch?v=TMnOg87-29A&feature=related

This is one way that someone decided to get around the disabling of text comments in the original posting.

I have no idea whether this was done in order to discredit the video - or by someone who wanted legitimate discussion.

Another Strong Presentation David.

Well done. Thanks for your tireless work for the cause of Truth.

Window of opportunity...

...in discussion of Blueprint for Truth, at Professional Pilots' Rumour Network. Register free and leave comments here: http://www.pprune.org/jet-blast/358008-9-11-time-another-look.html

Publish or perish

This should be transformed into a publication challenging prof. Bazant's papers.

Personally, I'm not sure if everything is so clear, since static and dynamic resistance of bottom floors are something completely different.

That's said, I always thought this is the direction that should be pursued.

Measure, measure, measure and compare with the theory...

Publication

> This should be transformed into a publication challenging prof. Bazant's papers.

I'm planning to do that.

> Personally, I'm not sure if everything is so clear, since static and dynamic resistance of bottom floors are something completely
> different.

I don't understand this comment in the context of this video.

Bazant

Here is an Empirical paper that debunks Bazant

http://911blogger.com/node/19281

Tony Szamboti said this about it.

"I think this paper is quite powerful and should be published so it's effect is long lasting."

and

"This paper should be published.as It does an excellent job of bringing in the mass aspects and putting everything together."

and has been working with and encouraging me to improve it.

Frank Legge said this in an e-mail

"I think this paper is a good contribution. It should be a powerful counter to the Bazant/NIST theory which now has pride of place in the public mind"

He thinks it should be peer reviewed

David Chandler said this

"On Tony Szamboti's encouragement I am reading it more carefully again. I paused at the Work tutorial. I am liking it so far".

And wanted to discuss it in an e-mail, but ... no contact?

It would be nice if someone contacted me even if its to say that the paper isn't suitable for publication and maybe the reasons why, but I've heard nothing from these folks :-(

And there is at least one fan of this paper out there, so thanks Satyakaama for this comment.
http://911blogger.com/node/20533#comment-211066

"I'll defer to the experts here, but shouldn't no_body's paper be peer-reviewed and (widely) published?
It's very detailed and persuasive. Unless Im overlooking something, it's one of the best papers I've seen on the WTC "collapse.""

convinced

the impecable logic of your analysis on the "collapse" of the 1wtc is what finally convinced me, beyond reasonable doubt, that the official theory is wrong