Pat Curley of the Screw Loose Change blog also debunks himself in his entry a "A Spot of Debunking" when he states:
Nobody has explained why controlled demolition should be as fast as free-fall speed in the first place. This seems to be just assumed.First of all, as is pointed out in the video a slowing of the descent of the building as it begins to pile up and encounter resistance is to be expected. Secondly, the more reputable 9/11 researchers like Jim Hoffman of the website 911research.wtc7.net have never claimed that the buildings fell at exactly free-fall speed.
Here's a page with the Southwark Towers demolition, which Steven Jones cited in one of his lectures as a very good comparable for the WTC. You have to click on the third icon from the left on the bottom row to see this demo.
Watching carefully, I estimated that the roof on the left building started sagging right around 38.24 into the movie, and that the top of the building hit ground at about 45.69. Thus the duration of the collapse was about 7.45 seconds. From this page we know that the roof of the building was about 98 meters high, or approximately 323 feet. But a building of 323 feet should not take 7.45 seconds to collapse in free fall, it should only take 4.5 seconds by the formula 16*4.5^2=323.
And indeed, there is no reason to expect that controlled demolition results in a free-fall collapse of a building.
In regard to the Twin Towers Hoffman states that the Towers' tops fell virtually unimpeded. He points out that "in a vacuum, a block of wood (or lead) would take 9.2 seconds to fall from the tower's roof," but this does not factor in air resistance, which alone could account for the 15 second fall time, he states:
The official story requires that more than air resistance was slowing the descents. The falling rubble would be having to crush every story below the crash zone -- ripping apart the steel grids of the outer walls and obliterating the steel lattice of the core structure. The resistance of the intact building itself would be thousands of times greater than air resistance.Again, in regard to WTC 7 Hoffman points out that it plunged at a nearly free-fall rate.
If air resistance is able to increase total collapse times by even 20 percent, then shouldn't the addition of the resistance of the buildings themselves increase the time several thousand percent, to at least tens of minutes?
Of course the idea of a collapse lasting minutes is absurd. So is the idea of a steel frame building crushing itself.
Debunking the Debunkers' Free Fall Fallacies
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