Quote:He says it would have taken the South Tower 9.2 seconds to collapse. That might be true if we assume that the South Tower started collapsing at floor 110.
Zippo, this is really easy to adress.
Do you believe the South Tower started collapsing at floor 110?
We're not concerned where it started, you would only be interested in that if you wanted to prove the pancake theory, we're talking about the whole object [towers] falling, South Tower may have been blown up! from 110 floor, the point is how long it took the
top of the tower to reach the
bottom (freefall ?).
The towers were 1350 and 1360 feet tall. So let's start by using our trusty free-fall equation to see how long it should take an object to free-fall from the towers' former height.
Distance = 1/2 x Gravity x Time(squared)
or
Time(squared) = (2 x Distance) / Gravity
Time(squared) = 2710 / 32 = 84.7
Time = 9.2
So our equation tells us that it will take 9.2 seconds to free-fall to the ground from the towers' former height.
Using our simpler equation, V = GT, we can see that at 9.2 seconds, in order to reach the ground in 9.2 seconds, the free-falling object's velocity must be about 295 ft/sec, which is just over 200 mph.
But that can only occur in a vacuum.
Since the WTC was at sea level, in Earth's atmosphere, you might be able to imagine how much air resistance that represents. (Think about putting your arm out the window of a car moving half that fast!) Most free-falling objects would reach their terminal velocity long before they reached 200 mph. For example, the commonly-accepted terminal velocity of a free-falling human is around 120 mph. The terminal velocity of a free-falling cat is around 60 mph. (source)
Therefore, air resistance alone will make it take longer than 10 seconds for gravity to pull an object to the ground from the towers' former height.
On page 305 of the
9/11 Commission Report, we are told, in the government's "complete and final report" of 9/11, that the South Tower collapsed in 10 seconds. (That's the government's official number. Videos confirm that it fell unnaturally, if not precisely that, fast. See for yourself:
QT Real)
But as we've just determined, that's free-fall time. That's close to the free-fall time in a vacuum, and an exceptionally rapid free-fall time through air.
But the "collapse" proceeded "through" the lower floors of the tower.
Those undamaged floors below the impact zone would have offered resistance that is thousands of times greater than air. Recall that those lower floors had successfully supported the mass of the tower for 30 years.
Air can't do that.
Can anyone possibly imagine the undamaged lower floors getting out of the way of the upper floors as gracefully and relatively frictionlessly as air would? Can anyone possibly imagine the undamaged lower floors slowing the fall of the upper floors less than would, say, a parachute?
It is beyond the scope of the simple, but uncontested, physics in this presentation to tell you how long the collapse should have taken. Would it have taken minutes? Hours? Days? Forever?
Perhaps. But what is certain, beyond any shadow of a doubt, is that the towers could not have collapsed gravitationally, through intact lower floors, as rapidly as was observed on 9/11.
Not even close!
In order for the tower to have collapsed "gravitationally", as we've been told over and over again, in the observed duration, one or more of the following zany-sounding conditions must have been met:
* The undamaged floors below the impact zone offered zero resistance to the collapse
* The glass and concrete spontaneously disintegrated without any expenditure of energy
* On 9/11, gravity was much stronger than gravity
* On 9/11, energy was not conserved
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B.t.w photos here of a perfect WTC Towers pancake theory
:
http://www.plaguepuppy.net/public_html/gallery/Explosions.htm