Reply #30: Here is a 911 skeptic that disagrees..

[hack89]

http://www.erichufschmid.net/WTC_AnalysisRussell.html

Note that he indirectly illuminates a huge potential hole in Hoffman's argument, namely that due to the massive potential energy the WTC towers had, it would have take huge quantities of explosives to make up the difference Hoffman says he calculated. This does, however, provide the 911 research community a means by which to calculate how much explosives were used - I wonder why Hoffman didn't take the extra step? Perhaps he didn't like the answer?

How much difference would explosives have made? As a particularly massive example of controlled demolition, the Kingdome weighed 110,000 tons:
http://abcnews.go.com/sections/tech/Geek/geek000316.html

and required 5000 lbs of dynamite to destroy:
http://seattlepi.nwsource.com/local/stack05.shtml

So we might guess the amount of powder required to demolish a WTC tower might be as much as 30,000 pounds (or perhaps less, given the much taller and more lightly built structure). The energy content of dynamite is given as only 0.47 kwh per pound:
http://www.elorantaassoc.com/eob97.htm

Thus, if explosives were used, they would only have contributed about 15,000 kwh, which is largely negligible compared to the gravitational energy. In a controlled demolition, gravity does the lion's share of the work, while the explosives serve only to destroy the physical integrity of the structure.