Jack White Posted July 12, 2007 Share Posted July 12, 2007 (edited) Jeff King, PhD (Electrical Engineer, Graduate of MIT) http://www.livevideo.com/video/DB001627693...ctural-eng.aspx Re the collapse of the Twin Towers... At the simplest level there is a gross violation of conservation of energy: for the towers to fall at or near free-fall speed, all the stored gravitational energy would have had to be used to accelerate their own mass downward. The same energy can’t be used twice, which is to say that any “work” extracted, for example, to pulverize concrete, will slow the collapse by a corresponding amount. In the case of the twin towers even a rough calculation of the amount of energy needed to pulverize all the concrete and gypsum to the very fine dust observed (and without including the energy needed to crumple and deform steel) indicates that it would have far exceeded the entire gravitational potential energy of the structures. As measurements by Cahill have shown, dust particles were mostly <30 microns, with a sizeable fraction smaller than 0.25 micron. Not only is an immense amount of energy needed to break most of the chemical bonds holding the concrete together, but there is no mechanism that can be postulated with only a gravitational collapse that might account for such rapid and complete pulverization. Such a process is almost by definition an explosive event: the almost instantaneous conversion of a slab of concrete into a rapidly expanding cloud of dust. The obvious question is: what does it mean that there was a controlled demolition? At the simplest level, it means that someone had a lot access to the buildings over a long enough period of time to set this up. It implies, as many other things, that the people who had effective control of the site had an interest in having it scrubbed and making sure that no information was available; that a forensic reconstruction couldn't be done. Even in much smaller catastrophes we typically will reconstruct things as completely as possible. For example with TWA Flight 800 pieces were dredged off the bottom of the sea. A complete reconstruction was done to allow a detailed analysis. In this case, just the opposite was done. Edited July 14, 2007 by Evan Burton Removed misleading discription of Jeff King Link to comment Share on other sites More sharing options...
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