That document (BilliardBalls) looks pretty superficial to me.  Looking
at figures 5 and 6, which use the 'billiard ball' theory to determine
'minimum time for collapse' times of 30-90 seconds, they appear to make
the assumption that as each floor collapses, the entire upper collapsing
structure *stops*, and the next floor (apparently with everything above
it) then begins to fall from zero velocity; i.e., no momentum transfer
at all.  It appears that she is claiming that all of the energy of the
falling upper floors is consumed in pulverizing the concrete and causing
the next floor failure.

This appears to be a much more thorough analysis:
http://www.911myths.com/WTCREPORT.pdf 

It would be interesting to reconcile these two papers in detail.

Gary


> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Mark E. Skeels
> Sent: Tuesday, December 05, 2006 7:15 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [OT] Physics denies official 9/11 report.
> 
>  From the page:
> 
> 
> "The World Trade Center Towers as Bio-inspired Structures:
> Characteristics of their Design and Demise
> 
> This work was presented at the 2006 Society for Experimental 
> Mechanics 
> Annual Conference
> Adam's Mark Hotel St. Louis, Missouri USA June 7, 2006
> by Dr. Judy Wood, professor of Mechanical Engineering "
> 
> http://janedoe0911.tripod.com/BilliardBalls.html
> 
> Mark
> 
> Gerhard Fiedler wrote:
> > James Newtons Massmind wrote:
> >
> >   
> >> Others have said that the weight of the top floor would 
> accelerate the
> >> lower floors and account for the rapid fall. That is an interesting
> >> point, which may very well be correct. I don't know. I 
> would love to
> >> hear from someone who does. 
> >>     
> >
> > If it falls from the top, the weight of the top ceiling 
> crashes on the
> > floor below. There it "shares" its energy and momentum, and 
> both continue
> > to fall, however slower as if there were no floor below. 
> And so on. To fall
> > nearly like free fall, I'm pretty sure the whole steel 
> frame has to crash
> > at nearly the same time (between all floors). 
> >
> >   
> >> However, from all the videos, it is very clear that it 
> started falling
> >> from the bottom, not the top. If fires heated the steel, 
> why wouldn't
> >> the top have fallen first?
> >>     
> >
> > Maybe because the load is much higher at the bottom, and a 
> much lower
> > temperature is needed to soften it to a point where it 
> gives in? But even
> > then, in order to fall in a time that's close to free fall, 
> the whole steel
> > frame has to give in at nearly the same time. Which may be possible.
> >
> > Gerhard

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