Thank you, Harry! Haven't gone over those numbers with a calculator and CRC yet but it looks good at first glance -- and it provides a great place to start even if I end up disagreeing!
Harry Veeder wrote: > > A calculation can be found here near the end of the page: > > http://www.takeourworldback.com/smokinggun.htm > > quote: > > <<As for the kinetic energy available from the massive collapse, this is > given by: > > KE = 0.5mv^2 where v = SQR(2gh) which leads to KE = mgh > > ...and if all of this was converted to heat and remained within the > material, the temperature increase is found by dividing by the mass and heat > capacity: > > T2 - T1 = mgh/(mc) leading to gh/c > > So for g = 9.807 m/s^2, h = 1368 / 3.2808 m, and c = 450 J/kg.K for steel at > around ambient temperature, the mean temperature increase is 9.09 degrees > Kelvin. The concrete would be cooler; its specific heat is nearly twice that > of steel. > > This is already a very high estimate for the mean, since that supposes the > entire building mass was dropped from 1368 feet. There should be a reducing > factor of more than 2, considering the steel was much heavier grade at the > bottom, and a considerable amount of the building's mass was below ground. > > 400,000 tonnes distributed over an area of more than 4,000 square meters > averages less than 100 tonnes per square meter. There would not be spots > where a few pieces of steel would experience temperature increases that were > hundreds of times greater than the mean increase. If a couple of trucks > collided head-on, tens of tonnes of mass would be distributed over a > cross-section of a few square meters and the impact would be very sharply > concentrated over tens of milliseconds as opposed to ten seconds or more. > Such collisions do not result in puddles of molten metal on the road. And > unfortunately for the "gravitational energy melts steel" theory, even if the > steel was already hot, it still requires some 250 KJ/kg for the latent heat > of fusion to melt it, which is over 60 times the energy needed to raise > from, say, 25 C to 34 C.>> >
