Wednesday, May 03, 2006

I Take It They Flunked High School Physics

At the 35:45 mark our intrepid filmmakers try to use some physics to prove the World Trade Center was imploded. The claim that Galileo's law of falling bodies proves the following:

With 1362 being the height of the tower. Actually what Galileo proved was that falling objects acelerated at a constant rate (delta d = 1/2 a(delta t) ^2 ) with a=32 feet per second. Thus, they surmise, something would fall 1362 in 9.2 seconds. The first tower collapsed in about 10 seconds, so they conclude that it was in "a free fall" that could only be caused by an controlled demolition.

They have set up this high school physic problem wrong though. Remember, the collapse of the towers didn't begin at the tip of the radio antenna, it began at the bottom of the area damaged by the crashing planes, which in WTC2 case was about .79 times the height of the tower or about 1075 feet. Additionally, it didn't fall all the way to the ground, since it was piled up on all the other collapsed floors beneath it, so a more accurate number would be about 1000 feet. So the number they should be using is 7.9 seconds, not 9.2, indicating that it was not as much of a "free fall" as they claim.

This whole theory is bizarre anyway. We aren't talking about a falling apple here. Consider the forces involved, as MIT engineering professor Eduardo Kausel explains:

Kausel also reported that he had made estimates of the amount of energy generated during the collapse of each tower. "The gravitational energy of a building is like water backed up behind a dam," he explained. When released, the accumulated potential energy is converted to kinetic energy. With a mass of about 500,000 tons (5 x 108 kilograms), a height of about 1,350 ft. (411 meters), and the acceleration of gravity at 9.8 meters per second 2, he came up with a potential energy total of 1019 ergs (1012 Joules or 278 Megawatt-hours). "That's about 1 percent of the energy released by a small atomic bomb," he noted.

Once the towers started collapsing, they were practically in a free fall, there was nothing that could stop that kind of force.


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