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Posted by The Natural Philosopher on 10/17/07 15:17
schoenfeld.one@gmail.com wrote:
> Most people don't know that there were actually 3 buildings which came
> crashing down on the day of 9/11.
>
> The third building, WTC 7, can be seen here
>
> http://video.google.com/videoplay?docid=-7750532340306101329
>
> There is no mention of this building in 911 Omission Report.
>
> Can fire make a building come crashing down at free fall speed?
>
Yes, mist definitely it can.
> If you think it can, patent the idea and make billions in the
> demolitions industry!
Why? its far less controllable than systematic demolition or controlled
explosions, generates more pollution, is more dangerous and moe expesnive.
>
> How do we know WTC 7 was demolished?
>
WE do not. Neither do you. You just believe what you want to believe.
> If WTC 7 collapsed in 6 seconds, and it takes 6 seconds to free fall
> from the roof of WTC 7, then you got it - WTC 7 underwent a free fall.
>
Exactly. Thats what heppens when you destroy the lower section of any
building BY ANY MEANS to the pint at which a progessive collapse occurs.
> This means as the each floor was falling straight to the ground it did
> so without crashing into anything on the way. ONLY CONTROLLED
> DEMOLITION CAN ACCOMPLISH THAT!
>
Utter bollocks. Uncontrolled demolition is exactly the saame reult.
> PROPOSITION 1:
> It took a total of 6 seconds for the roof of WTC 7 to reach the
> ground. This proposition is supported by the empirical,
>
> http://video.google.com/videoplay?docid=-7750532340306101329
> Collapse start time: 17 seconds
> Collapse end time: 23 seconds
> Total collapse time: 23-17 = 6 seconds
>
> PROPOSITION 2:
> A free fall from a height equal to the roof of WTC 7 would take 6
> seconds. This proposition derives trivially through (Galilean)
> kinematical considerations alone:
>
> Displacement = initial velocity * total time + 1/2 * acceleration *
> total time^2
>
> or
>
> s = ut + 1/2at^2
> where
> s = 174 m (height of building)
> u = 0 m/s (building was stationary prior to collapse)
> a = 9.8 m/s^2 (since gravitational field strengh averages at
> a constant)
>
> Thus,
> 174 = 0 t + 1/2 9.8 t^2
>
> Solving for t
> t = sqrt( 2 * 174 / 9.8)
> = 5.9590
> ~ 6 seconds
>
Totally irrelevant: you have missed the whole point. In a steel framed
building once Euler buckling of a structure like that begins, the effect
is rapid and dramatic. Euler buckling is an instability issue: once it
starts it finishes..it does NOT happen gradually.
You can test of for yourself by bulding a tower out of e.g. balsa wood
and sticking a weight on top. Light a small fire in the base and watch..
Oh sorry. You don't do engineering do you? only conspiracy theory.
Easier to believe that the whole thing is a Jewish plot than that the
trade center and the adjacent buildings were simply not very well
designed, and certainly not designed for the sort of stresses and
temperatures they found themselves subjected to.
In general a steel frame building is designed to withstand about 45
minutes of fire. In that time the building is expected to have been
evacuated and the fire brought under some sort of control. In fact the
buildings just about stood that long. What had not been anticipated was
that they would be subjected to such a large fire for so long, with
people trapped above it, and with no means of fighting it. The designers
went only as far as the regulations and standards insisted that they
should. No one insisted that, in the event that a very intense fire did
continue for 45 minutes plus in the lower parts, that the structure
should fail 'gracefully' : Indeed to engineer such a structure is a huge
challenge. To do it economically is almost impossible. You probably want
a geodesic type structure, and even those are not immune from
catastrophic failure.
If you have a real interest in understanding the truth, study some of
the WWI airframse and the reports of how aircraft broke up under fire to
get a bit of a picture.
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