You posted this...
Air pressure from the building accounts to 10-20m flight. And that would require the body to be preground to tiny bits. Otherwise we would need it first to stay inside to be pinned and fall down to get ground up.
If you want to experiment, climb to the roof of a tall building, put e.g. piece of meat with some bones in it on the edge, drop a concrete tile on it, and measure if you can get those pieces flying 200m. You can apply free fall, no need to take the steel superstructure into account.
I'm very sorry for your loss, I'm very sorry for all the lives lost due to war on terror. Your friend goes to same category with +1.000.000 other victims.
What Actually happened? do you want a 1000 page version or 50 word version?
...just 3 minutes after I had explained it all to you, and while I was still doing some edits. Perhaps you missed my post? Directly above yours.
Let us do a quick calculation on a simple model:
Let us assume that the first floor to collapse did so by coming down vertically, at 0.7g, until it hit the floor below.
Each story was 12 feet high. Subtracting 4 inches for the thickness of the concrete slabs plus a bit for ceilings, floor covers, office contents, that will work out to a drop distance of 3.5 meters (being European, I prefer metric).
0.7g is 6.8635 m/s
2
Velocity after moving s=3.5 m at a=6.8635 m/s
2, from rest, is
v(3.5 m) = SQRT(2*a*s) = 6,93 m/s.
And this took
t(3.5 m) = SQRT(2*s/a) = 1,01 s.
Let's make that 1 s even
The story, from floor to metal deck, has an volume of 63*63*3.5 meters filled mostly with air and movable objects. That's 13,891.5 m
3 of air, which get blown mostly out the windows (some can escape up and down the core shafts, giving rise to pressure pulses in other stories). Window openings are 2/3 of the width of the facades (column width is close to 1/3 column distance center to center) - 63*4*2/3 = 168 meters - and 2,34 meters high (vertical distance between spandrels), so air can escape through a maximum of 393.12 m
2 of openings.
Of course, openings get smaller as the floor collapses - from 393.12 m
2 to 0. I'll ignore that effect for the moment.
So 13,891.5 m
3 of air are escaping through 393.12 m
2 of openings within 1 s of time - that should work out to an
average air speed of over 35 m/s = 127 km/s = 79.5 mph (just divide the two numbers).
This is ignoring that openings get smaller as the floor collapses. Near the end of that second, with collapse velocity the highest and openings the smallest, nozzle velocities will be MUCH higher than that.
Starting from a height of ca. 300 meter (South Tower; North Tower higher), objects of suitable size should be able to travel some distance when blown out with such high winds.
On the second floor and all that follow, air will escape a
lot faster (although more victims from the plane crashes were probably above the first collapsed floor than below - a bit more tricky to assess collapse velocity of the floors above relative to the collapses zone where floors are piling up).
ETA:
We need two mechanisms for the dismemberment of people: One that accounts for body parts that were ejected during the collapse. You already agreed that the plane crashes can easily account for more than 100 victims being shred to suitable pieces. And another that accounts for those bodies not identified at all. That one is easy, too: They all fell from a hieght of 300 or higher, and had an average of 10-12 floors collapsing down on them, in a chaotic avalanche of 300,000 tons of steel and concrete per tower. And then their remains were subjected to weeks and months of fires, then rain, possibly episodes of acidic considtions etc., all of which degrade body tissue to an extent that can make it unrecognizable or unidentifyable.
You seriously underestimate air pressure and air speeds as floors 63x63 meters wide collapse. See above.
We have two explanations. You incorrect one, and the reality I just described.