Building 7 collapsed at freefall speed - impossible unless demolition methods were used

The information in this top section is from the NIST report on building 7, page 45
The first graph shows the 3 stages of collapse of building 7.

According to NIST a free fall drop lasted for 105 ft. from time 1.75 to 4 seconds during stage 2 on their graph.

But instead of using the slope found at stage 2, which represents instantaneous acceleration, they used the first and last data points on the graph including stages 1 and 3. This is average acceleration, and where the "40% longer than the computed free fall time" for 18 stories to collapse comes from.
But for their graph, average acceleration is a meaningless number because it is clear that there are 3 separate stages of acceleration, the main one showing free fall acceleration.

"A free-fall time would be an object that has no structural components below it"-- Shyam Sunder of NIST

"The interesting fact is that each of these 110-story Twin Towers fell upon itself in about ten seconds at nearly free-fall speed. This violates Newton's Law of Conservation of Momentum ... the prevailing theory would have us believe that each of the Twin Towers inexplicably collapsed upon itself crushing all 287 massive columns on each floor while maintaining a free-fall speed as if the 100,000 or more tons of supporting structural steel framework underneath didn't exist."-- William Rice, P.E., Why the Towers fell: two theories, Vermont Guardian, March 1, 2007.

It is not possible for a 110 story building to collapse naturally in 10 seconds - as fast as an object thrown off its roof would fall to the ground. All the floors underneath the impact hole were intact and undamaged. For the building to fall in 10 seconds, every rivet, every weld, every girder on each floor would have to fail every tenth of a second (since 10 floors "collapsed" every second).

Beneath the impact areas, the buildings should have been as strong as they'd ever been and just as able to continue supporting the same weight they always had.

We saw what looked like the towers falling straight down through all the undamaged floors of the building -- for each tower, through 100,000 tons of steel, 210,000 cubic yards of concrete, desks, computers, filing cabinets, toilets, furniture, etc.

That takes time.
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Last updated April 2020.