From: Mike Lorrey (mlorrey@yahoo.com)
Date: Sun Oct 13 2002 - 20:06:07 MDT
--- Lee Corbin <lcorbin@tsoft.com> wrote:
> Robert wrote in some thread
Actually, it was me.
>
> > Each collapse triggered a 2.7 richter earthquake. Each tower was
> > about 40,000 tons of material (not pounds). That's 80 million
> > pounds of material, striking the earth at 250 mph (367 fps).
> > Kinetic energy equals mass times velocity squared, or
> > 10,775,120,000,000 ft-lbs/sec for each tower collapse.
> > How many tons of TNT is that equal to?
>
> Energy should come out in ft-lbs, and one foot-pound apparently
> is 1.356 joules (I looked it up---my failure to work this out
> from first principles is humiliating). So if you are correct,
> then this translates to 1.07 x 10^13 joules, no?
I misstated the units, which should be ft-lbs^2/sec^2. Foot-lbs are a
measure of torque, with no time component. My mass estimates are based
on my recollection of the amount of debris that Mayor Guiliani said
needed to be excavated from Ground Zero, which was 100,000 tons, and
was made up of not just the two main towers, but the subsidiary
buildings as well.
>
> A handy thing to remember whenever you're thinking of how
> much megatonnage a volcano requires to throw some immense
> mass a half-mile into the air, or thinking about how many
> H-bombs it would take to literally blow up the world (i.e.,
> give every atom of the Earth escape velocity) is
>
> 1 megaton = 4x10^15 joules.
>
> In fact, the source for this is my old copy of "Spacetime
> Physics" by Taylor and Wheeler, p. 136. Two of the factors
> they use to derive this are "10^3 calories/gram of TNT-
> equivalent" and "10^6 grams per ton", so we know that this
> is a pretty rough calculation.
>
> Anyway, your 1.07 x 10^13 joules works out to about .0027
> megaton, or 2.7 thousand tons of TNT. The little Hiroshima
> bomb was 5,000 kilo-tons, I believe.
The Hiroshima bomb was about 12 kilotons of TNT. I understand that the
backpack nukes that the Russians can't seem to keep track of are in the
4-8 kiloton range, mere tactical weapons. 9/11 was about half the
destructive power of the sort of nukes we are worried about bin Laden
getting ahold of. The one's Saddam is intent on building are apparently
more in the W-88 range (250 kilotons or more). So while al Qaeda is
certainly a significant threat, I think Saddam is intent on gaining far
greater capability (and is willing to use it).
Keep in mind that my force estimate was for EACH tower, not them
together, since they fell at separate times.
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