poor americans...

[nihil]

Hi Aard~,

"kilotons" does not refer to dynamite, it is a measurement against T.N.T. (trinitrotoluene). The power weight ratio of C4 to T.N.T. is 1:1.34

So, 20/1.34 = 14,925 tons of C4

The current (UK) price is £15 per kilo ex-works.

As for debris flying out...gee, two big towers falling down have a lot of KE, surely enough to send some of the debris upwards

A sort of "dead cat bounce" effect?

EDIT: Actually "debris flying out" is probably more "falling away from"? If you look at how these buildings are constructed you will see that they all have external cladding which would fall off once the ties to the internal skeleton were severed. How these substantial panels would behave in free fall is rather unpredictable. Suffice it to say that it wouldn't be like a house brick.