Reply #56: D P Grimmer, Calculations on the Possible Use of Thermite [View All]

[Kai]

Have you read this paper?

http://www.physics911.net/thermite.htm

Calculations on the Possible Use of Thermite
to Melt Sections of the WTC Core Columns

by D. P. Grimmer

Version 1.1, June 20th 2004

excerpt;
The observed near free-fall times of the WTC towers (and WTC7) were a dramatic signature of a controlled demolition. (The articles at http://members.fortunecity.com/911 are a valuable resource for presenting and then challenging the "official" explanation for WTC collapses). Measured times are all around 10 seconds, which is close to calculated free-fall time, indicating the tower floors fell without much impediment. They essentially fell into air . The theory put forth by T. Eagar of MIT and other "establishment" engineers is that while no steel members actually melted or failed, the floor assemblies, bolted at their joists to the outer walls and inner core structures, did fail . The floor joists attachment bolts were weakened and gave way, twisting sideways and allowing the initial floor to "unzipper" itself all the way round and collapse to the floor below. The remaining floors then pancaked all the way down. Never mind that floor joist cross-members, placed to resist twisting, and additional support structures were not included in the MIT/FEMA/NOVA calculations and presentations (nor was the inner core collapse mechanism explained at all).

Consider the following: if the pancaking effect caused the total building failure, why is it that no video of either of the WTC collapses shows any sign of stutter between floor collapses, which should have been very apparent especially in the first few floors of collapse when the speed of gravitational collapse was small? Consider also that apologists for the official conspiracy theory propose that 30% of the gravitational collapse energy was necessary to create the pyroclastic cloud of debris: that is, in their own analysis, this energy came out of the gravitational energy. This means that the time of fall would have been slowed further than what was observed. When a body of mass m falls from a height h, acted upon by gravitational acceleration g, it converts its potential energy PE = m x g x h into kinetic energy KE = (1/2) x m x (v exp2). Here h = (1/2) x g x (t exp2), t = time of fall, and v =g x t, where v = velocity. Removal of 30% of the PE to pulverize concrete essentially reduces the amount of energy available from falling, effectively reducing the gravitational acceleration to something less than g.

Substituting, in the above equations we have (1.0 - 0.3) x PE = 0.7 x PE = m x g' x h, where PE, m and h are as before and g' = the effective gravitational acceleration. Hence, comparing terms for PE, g' = 0.7 g. The time of collapse under g' will also increase. If we let the effective collapse time be t', then comparing terms for constant h, (1/2) x g x (t exp2) = (1/2) x g' x (t' exp2) =
(1/2) x 0.7g x (t' exp2). Hence, (t exp2) = 0.7 x (t' exp2), or (t/t') = SQRT (0.7) = 0.837. Or, t' = 1.195 t.

Now the observed time t = 10 seconds (a free fall time, the fastest possible time under g = 9.8 m/sec/sec = 32 ft/sec/sec = 32 ft/s exp2). For the cloud debris creation to absorb 30% of the gravitational energy, the observed time of fall would be 10s x 1.195, or almost 12 seconds. This long a collapse time was observed by no one. Clearly, there are serious flaws in the official explanation/conspiracy theory.

The implication from the above is that there were major energy sources other than gravitational involved in the WTC towers collapses. Certainly that is the conclusion of J. Hoffman in his thorough discussion of the north WTC tower dust cloud . By calculating the major sources and sinks observed, particularly the sink of the pyroclastic cloud expansion, Hoffman establishes that a large amount of energy had to be available to drive that expansion, in a (minimum) range of 2,706,000 kWh to 11,724,000 kWh (see his Summary table). Hoffman does not propose an energy source to balance that sink. In Appendix B, an estimate, for discussion purposes only, of the amount of thermite-equivalent to provide this energy source is discussed. It is large, but physically possible.