Seffen's "Ordinary Explanation"

Oh, I do so love how Winter Patriot is vigilantly dogging and debuking Dr. [sic?] Seffen’s attempt to paint the 9/11 WTC collapse as “a very ordinary thing to happen”!!!
Rebuffed! Conspiracy Theory Destroyed By Unsung Internet Heroes
Thursday, November 15, 2007
Defenders of Cambridge's Dr. Keith Seffen [photo] and his paper, "Progressive Collapse of the World Trade Centre: a Simple Analysis", are popping up everywhere. Well, not everywhere, but they're popping up in a few places. And with one reasoned rational argument after another, they have taken me apart.
On Sunday, I posted a review of Dr. Seffen's paper , and based on the reactions that piece received, I thought I had done a fairly good job of treating it calmly and rationally. But it turns out that I have been deceived by yes-men and weak-kneed courtiers. The review was shoddy, full of holes, politically motivated and shameful in the extreme.
…R. Steve Walz explained what was wrong with my analysis:

Dr. Seffen assumes that a constant force, supplied by the suddenly unsupported top of the tower, was pressing down, crushing each story, one after another, all the way down to the ground. An elementary understanding of physics would tell you that this is not possible, unless the top section of the building -- the part doing the crushing -- were made of much denser material than the bottom section -- the material being crushed.

So Dr. Seffen and I were both wrong. The total force increases! And it's not even limited by air resistance! I've always thought some truthers were off in fantasy land with claims that the towers collapsed "faster than free-fall speed". How could that happen, I wondered, unless a force were pushing down on the falling concrete?
…It was an internal explosion. It wasn't limited by air resistance. And it reached speeds well in excess of terminal velocity.
…In the case of the WTC, the material being crushed was nearly identical to the material doing the crushing. In fact, the structural steel was thicker at the bottom than the top, in which light Seffen's model appears even less appropriate to the event (not that this makes very much difference in the long run).
…And therefore all the debris that went whooshing down the streets ... it was actually still pushing down on the towers at the very same time!
This is a very detailed post and it’s essential to read it yourself. I will provide just one more tidbit to wet your appetite:
…The collapse generated the heat that melted the metal that flowed out of the building just before it collapsed. It makes perfect sense if you repeat it often enough.
http://winterpatriot.blogspot.com/search?q=9%2F11+%2B+WTC+collapse