It's late now and let me try to make my point.
Your argument is that for WTC7 to be in near-free-fall, some explosives must be moving mass out of the way of the falling building because otherwise the principle of conservation of momentum will slow it down.
You say that at 13:30 in this clip:
"So obviously to get free-fall somehow you must have moved hundreds of thousands of tons of material out of the way."
Then you go on to state that you need explosives to move the material out of the way.
Quoting you in reply #205:
Oh, brother, MH -- as I said, it is not a matter of the beams becoming weak - like spaghetti -- it is a matter of the MASS remaining in place (or not, for free-fall), even if held by a thread!
I even gave you the equation referring to conservation of momentum. Look, have you ever studied what happens when mass M at speed V hits another mass M in its path? The speed drops by ONE HALF! Thus you cannot maintain free-fall acceleration at g= 32.2 ft/s**2 if there is MASS in the path, only if the "spaghetti" (it still has mass!) is moved OUT OF THE WAY! How do you get tens of thousands of tons (huge MASS) of steel and concrete, 100 vertical feet worth (and across the cross-section of the building, since the roof fall during this time is symmetric and UNIMPEDED for over 100 feet) to "evaporate" -- or co-fall or get out of the path? Explosives!
Study up on Newton a little would you? I'm running with family to a concert in 11 minutes plus a bit amused that conservation of momentum eludes you MH.
So you are clearly arguing that a model for WTC7 to fall at near free-fall speeds is to move mass out of the way with explosives. Without explosives then mass will be in the way and when moving mass A hits a stationary mass B then things have to slow down because of the conservation of momentum.
Then you point to a paper that makes an argument that WTC7 could not possibly fall at free-fall speeds if there is a top-to-bottom pancake collapse. To repeat your quote, "These analyses will also show you how momentum considerations enter in (importantly!) as we consider the observed accelerated falling motions of WTC7 and Tower WTC1."
So the thrust of your argument is that something is amiss because WTC7 fell at near-free-fall speeds when it "should not" be doing that. In your clip above you clearly imply that anyone with common sense should recognize this also.
Then I presented my "compaction zone" model and clearly demonstrated that in fact the building could easily fall at near-free-fall speeds without any requirement for explosives. You simply have to recognize that the momentum of a falling 47-story mass of building can completely overwhelm any compaction zone energy drain that is trying to slow down the falling mass of steel and concrete. The falling mass of steel and concrete must weigh millions of tons and would possesses a near-astronomical amount of energy after it had fallen for a mere two seconds.
I do not believe in EITHER of these two models -- I have consistently maintained that EXPLOSIVES WERE USED IN THE DEMOLITION OF THE WTC, particularly WTC7. I am surprised that you seem to have missed this point! Professor Kuttler demonstrated that the "pancaking floor" model was BS.
Well, I have shown you that you don't need explosives to have WTC7 fall at near-free-fall speeds, nor are there any conservation of momentum issues to deal with in the compaction zone model.
The reason I brought up the electronics example was that in that case and in this case I got a strong sinking feeling when I read your replies. In both cases there was a tangible sense that you didn't want to really deal with the points head-on and you were implicitly dismissive of your own previous points and wanted to move on. So I am suggesting a pattern here that's a form of bait-and-switch, and that makes me uncomfortable.
The bottom line is this, if I feel it again I will let you know.
WTC7 fell at near-free-fall speeds and there was no need whatsoever for explosives to be used for this to happen. That is a fact as far as I am concerned and if people reading this agree with me then the argument about WTC7 is in a sense already over.
Nonetheless, there is Ion's issue to deal with and I think that you have a few other main points about the mystery of WTC7. I am pretty convinced that I can address the other issues and make a pretty convincing overall argument that although the collapse of WTC7 looked highly unusual, the fact of the matter is that upon closer examination there was nothing unusual about it at all. And I am just giving you my opinion and I am not an expert in structural engineering by any means and neither are you.
It's still fun debating the points. And to wax poetic for a second, there is an unfortunate hurtful angle to the whole WTC conspiracy theory "industry." I know that in a way you feel it is a patriotic thing to do to challenge the government and be a form of watchdog lest our liberties be taken away step by step and the world become that much more Orwellian. So challenging the government party line is an implicit form of patriotism. However, if you are wrong, like in this case, you hurt the families and the loved ones of the victims of 9/11. They have seen death right up close, someone is never coming home. And you can sway some of them to believe that evil people in the government have conspired to do this. How horrible and doubly-shocked and hurt they must feel because of this. And a lot of the "9/11 Truthers" are arguably unwitting dupes in the "9/11 conspiracy theory industry" that has grown up around this horrible terrorist act. If you want to look for evil, you can also look towards the people that milk the 9/11 tragedy for their own purposes. Anything to make a buck.