Justin Case wrote:

Steven Earl Jones is a professor of physics at Brigham Young University.
I say that would qualify him, so far none of his peers can refute his claims
with any evidence. Many do agree with him that an unpartial investigation
of 911 is needed.He invites anyone to provide evidence to counter his
claims,
maybe you should try if you feel up to the challenge.

http://en.wikipedia.org/wiki/Steven_E._Jones#WTC_Collapse_Hypothesis

Here is a link to the paper.

http://www.physics.byu.edu/research/energy/htm7.html

Jones lambasts the NIST for having "tweaked" its models of the
collapse. But the tweaking actually consists in adjusting
parameters to take into account empirical data. Does Jones
think that the NIST should have rather ignored the data?

The relevant data here concerns the sagging floor slabs and
the trusses pulling the outer columns in. This is clearly
observed in photographs and can be measured. It already
becomes quite severe about 10 minutes before the actual
collapse.

Jones's own controlled demolition theory has no need for this
evidence of progressive structural failure several minutes before
the observed collapse.

So he provides a short citation from an analysis of Lane
and Lamont in which they appear to advance the claim that
the columns could not have been so pulled. (Never mind
that this pulling in is not a "tweaked" result from the NIST
report but actual empirical data.)

The quote Jones provide with approval is this:

"the core columns cannot pull the exterior [i.e., perimeter]
columns in via the floor"

However, this is the continuation of the article Jones fails
to cite :

<quote>The NIST collapse theory also states that "floors weakened
and sagged from the fires, pulling inward on the perimeter columns.
Floor sagging and exposure to high temperatures caused
the perimeter columns to bow inward and buckle-a process
that spread across the faces of the buildings. Collapse
then ensued".

This is similar to some of our collapse proposals but no
mention of thermal expansion is made, the floor buckling and
lack of support to the columns seems to be entirely due to
loss in strength and stiffness in their view which we would
consider to be only part of the story.
However we await the publication of the final NIST report
in this regard.<end quote>

So, they were just explaining how thermal expansion due to
the fires play a bigger role in the observed floor buckling
than NIST acknowledges and not much pulling from the
core is necessary to explain the subsequent structural
failure.

Just another thing I'll comment on right not because it's
especially eggregious. Jones proposed that a gravity
driven collapse with intact steel colums could not
result in the observed duration of the collapse.

He asks "Where is the delay that must be expected due
to conservation of momentum - one of the foundational
Laws of Physics?"

He then offers a very short and confusing discussion
with no quantitative calculation at all. He cites three
supporting sources. First:

http://911research.wtc7.net/wtc/analysis/proofs/speed.html

But here we find no calculations at all and no mention even
of either momentum and energy. There is just a handwaving
argument to the effect that in order to crush everything that
has to be crushed, the collapse ought to take several "tens of
minutes"!

Jones also cites a book written by professor of religion and
theology. Griffin, David Ray (2004).  The New Pearl Harbor:
Disturbing Questions about the Bush Administration and 9/11.
There might be more discussion of momentum and energy
in this opus but I haven't checked yet.

Finally he cites "A recent (2006) analysis by
Mechanical Engineering Professor Judy Wood on the rapid
collapse of the Towers is instructive although preliminary:
http://janedoe0911.tripod.com/BilliardBalls.html"

Now this is really bad. Jones claims that the "official
story" does not mesh whith the law of conservation of
momentum. Yet it is clear that the whole argument in
this "instructive although preliminary" paper he cites
entirely rests on a complete misunderstanding of the
law of conservation of momentum -- this is m1*v1 =
m2*v2 -- which the author does not cite or even use
in any of her calculations except to claim that it
ought to be conserved.

The author first consider all kinds of wild scenarios
where floors fall (starting with the 110th floor) on
each other and just pass through each other as if
they were immaterial (no conservation of momentum
there)

Then she announces: "Now, let's consider momentum"

And she continues with a quite confusing discussion:

<quote>"Assume that the top floor stays intact as a solid block
weight, Block-A. Start the collapse timer when the 109th floor fails.
At that instant, assume floor 108 miraculously turns to dust and
disappears. So, Block-A can drop at free-fall speed until it reaches
the 108th floor. After Block-A travels one floor, it now has momentum.
If all of the momentum is transferred from Block-A to Block-B, the next
floor, Block-A will stop moving momentarily, even if there is no
resistance for the next block to start moving. If Block-A stops moving,
after triggering the next sequence, the mass of Block-A will not arrive
in time to transfer momentum to the next "pancaking" between Block-B
and Block-C.  In other words, the momentum will not be increased as the
"collapse" progresses<end quote>

Why? Why would there be no increase in momentum? Will
not "Block-B" which has absorbed the momentum of Block-A
continue to accelerate due to gravity until it impacts the next
block?

The wild scenario she seems to envisage in one in which
each floor is carried to the next one at the same speed the
collapse wave is traveling (downwards from the top
accelerating at g)) and then transfers all its momentum
to that floor (hence to continuation of the collapse wave
at g). Each floor then starts falling again at g and has
only been delayed for the time it takes to fall *one* floor.

And why assume without discussion perfectly elastic
collisions? She seems carried away by her billiard ball
analogy. If the collisions are only slightly inelastic
then her whole analysis seems vitiated.

There are many other problems in this and Jones' paper
but that is enough for now.