[Phys-L] Re: Here we go again. WTC brought down by aircraft, not.

["David T. Marx" <marx@PHY.ILSTU.EDU>]

This is nothing more than a "conspiracy theory" and politicized junk science.

Nova had a very nice documentary on the the physics and engineering of the towers and their fall in
2002.  Engineers did an extensive investigation...see http://www.pbs.org/wgbh/nova/wtc/

Also, check out this analysis by Thomas Eagar, Thomas Lord Professor of Materials Engineering and
Engineering Systems at MIT. See Eagar's article,
www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

        The buildings were constructed to be suspended around the central elevator shaft structure.  The
designers included the notion that these buildings could withstand a collision of a light plane,
but it was not designed to withstand a large commercial aircraft nearly full of jet fuel.  When the
intense heat weakened the structural integrity of the steel on the entire floor or two and that
supportive internal structure, the weight of the floors above was no longer supported.  As it fell,
it caused the downward collapse of all the floors below because they couldn't support the weight of
the falling material either.  The buildings fell straight downward.  The fire retardant insulation
on the steel was insufficient to withstand the kind of extended burning of jet fuel that occurred.
        When buildings are demolished, a set of ideally placed charges are placed around the base of the
structure such that the building will fall straight downward.  In the case of the towers, these
would have had to been placed at the base and the bottom failing would have been noticeable to all
watching.  I was watching, I saw no such thing.  Only the top floors fell on top of the lower
floors.  That's all there is to it.
        As for the collapse of building 7, I do not know anything about this, only what Stephen Jones
describes.  If he has video footage that shows that, he doesn't need the government to release
anything.  In fact, if he has video and photographic evidence for his claims, why call for an
investigation and  the release of documents?  This just tells me that he wants to raise doubt in
the minds of people to further some political agenda.

        Edgar says that when he saw building 7 fall, he understood then why the towers fell.

> Yes, that's why I subjected it, "Here we go again."
>
> bc, who does wonder about the third building's collapse; only two aircraft.
>
> Shapiro, Mark wrote:
>
> > That's for sure!
> >
> > Mark
> >
> >
> > -----Original Message-----
> > =46rom: Forum for Physics Educators on behalf of John Clement
> > Sent: Mon 11/14/2005 6:31 AM
> > To: PHYS-L@LISTS.NAU.EDU
> > Subject: Re: Here we go again.  WTC brought down by aircraft, not.
> > =20
> > I haven't looked at the tapes recently, but it is my distinct impress=
> > ion
> > that they clearly show that the top parts of the building collapsed f=
> > irst,
> > and then you can see the progressive crushing of the floors below.  I=
> > t looks
> > quite different from a demolition where the bottom floors collapse fi=
> > rst and
> > then the building just sinks into a pile of rubble.
> >
> > This visual evidence along with the difficulty in setting charges pro=
> > perly,
> > and the structural design evidence should convince most people that t=
> > his
> > hypothesis is probably incorrect.  But conspiracy theorists are never
> > satisfied by evidence.
> >
> > John M. Clement
> > Houston, TX
> >
> >
> > > > Professor thinks bombs, not planes, toppled WTC:
> cut
_______________________________________________
Phys-L mailing list
Phys-L@electron.physics.buffalo.edu
https://www.physics.buffalo.edu/mailman/listinfo/phys-l