Reply To: Engineering Prof releases draft report on 9/11 collapse of WTC Bldg 7 in NYC


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#47567 Reply

Clark

Look at what is still on the A&E9/11″Truth” site; Chandler’s
Downward Acceleration of the North Tower:

https://www.ae911truth.org/evidence/videos/video/11-downward-acceleration-of-the-north-tower

This argument predicts that no structure that has successfully stood can undergo accelerating collapse. This is a site of architects and engineers; for them to continue to promote this they must be either incompetent or dishonest.

Here, Chandler sets out his reasoning regarding WTC7:

https://medium.com/@davidchandler_61838/free-fall-131a94a1be7e

He repeatedly uses “free-fall” and “g” interchangeably, but they are not remotely interchangeable. Free-fall is a physical condition ie. something that happens to a real object in the real world, whereas g is a rate of acceleration ie. an intellectual abstraction, with no physical existence. To equate one with the other is like saying “it’s a mile to the shop, and it’s a mile to the dump, therefore the shop is the dump”. Just because something accelerates at g does not mean that it is necessarily in free-fall. I could crush a banana against the floor at g, but it wouldn’t be in free-fall. Yet Chandler writes this (in Part 2):

“In the case of WTC 7 the fact of an extended period of free fall has been established by direct observation and measurement. See Part 1 of this series. We can conclude that all of the potential energy was being converted into kinetic energy with nothing left over to do anything else”

No. Direct observation and measurement establish only acceleration of the roof-line at (pretty close to) g. To establish free-fall we’d have to observe the whole moving object, to establish that nothing else (such as the core) was exerting force upon it. But we can’t see the internals of the building, so we can’t assume free-fall. On the contrary, we should assume that the internal components are exerting forces upon the outer visible structure, and since we saw the penthouse collapse before the outer structure, we have excellent grounds to suspect that those forces are acting downwards.