Quote Originally Posted by Bruno View Post
I'm a real one Masters in Engineering, Electronics major. And I think Jockeys majored in math.

Structural analysis (strength theory) was one of my minor classes. Though I do not know the equations anymore, I still know enough of the basic principles to assert that if you knock out the load bearing bottom corner of a rectangular building, and heat the remainder of the steel structure, it is likely to collapse.
yep, I sure did. and although I haven't crunched the numbers (the prevailing theory is more than plausible enough for me, I don't really get worked up about that sort of thing) I agree with bruno's analysis. also, to address alex's comment, many airlines have to be going 300+ mph to take off, not kph. a Boeing 767 can fly weighing up to 114 tons (that's over 200,000 kilos) and cruises at 568mph under optimum conditions (913kph) although if you don't care about engine and airframe damage and are descending, you can go faster. (a terrorist bent on suicide doesn't care about damaging the plane, obviously)

using those numbers, we can see that each plane could generate up to 13.1 gigjoules of kinetic energy, which is equivalent to about 3.13 tons of TNT. (so, about 1/300th of 1 kiloton of destructive energy). while this is not enough to completely level a building of that size, it is definitely enough to completely ruin it's structural integrity.