Thank you.
I have skimmed that post and downloaded the wgite paper it refers to , which I intend to read later.
I will just comment on one concern that struck me, you seemed to say that a taller building would require a greater hinge action in order to tilt, surely the opposite is true?
No. Think of it like this -- as a structure gets taller, its moment of rotational inertia scales roughly as the square of its height. This means it takes an increasingly high force to get it turning in the first place. A tall structure is simply not designed to rotate, and so it will tend to buckle or crumble in the middle before it can support this force.
This is why a short structure, say an aluminum rod a meter long, can topple over with ease, but a very tall one -- even strengthened to match its height -- like a radio tower tends to bend in the middle rather than just topple.
Same principle applies to WTC 7. It was very tall and couldn't rotate as a unit anyway. Any rotation it experienced meant cross-ties and bracing would pull free, further reducing columns' ability to resist buckling. And the sheer height makes those buckling forces irresistible.
I applied the same technique to measure the roofline of the WTC1 collapse and found it to be around 7 m/s2, quite a significant force is needed to reduce the acceleration of so much mass by 2m/s2, so I thought it significant that the upper section of WTC1 had this and WTC7 did not.
See the thread with
Gregory Urich's comments. The main reason the Towers collapsed slower was because there was momentum transfer high in the air, between the upper and lower blocks. In other words, the Towers didn't all start falling at once, and the inertia of the lower blocks absorbed a good amount of the velocity. This doesn't happen in WTC 7. It all starts falling more or less at the same time, and as a result, there is no momentum transfer except at the ground. It's perfectly normal given the difference in phenomenology.
They stated that the first 18 floors took 5.4 seconds to fall.
And..? Where do we start the clock?
I have indeed been to rifle ranges.
The witness reports of the 'explosions' they heard are not that detailed.
Phrases such as 'a massive explosion', 'a sound like a clap of thunder' and 'a real ba-boom' are not easily interpreted as necessarily being less than 130dB.
Are you aware that the world record belch is almost 120dB?
I was
not aware of that, and it sounds horrifying...

I trust this is 120 dB at 1 meter, you didn't specify. NIST describes a sound 130 dB at 1
kilometer. To match that, you would need approximately the entire population of New York City belching, at that volume, in unison.
A demolition charge is not like a clap of thunder. What you hear is essentially a shock wave, a very, very sharp
CRACK much like a rifle shot or a sonic boom. There is no conceivable way this sound could have been muffled. It would have appeared on virtually all of the recordings near the event, to say nothing of the very sensitive detectors described by Protec that even captured the air motion from the collapses.
It is also extremely unlikely that, had a demolition taken place, there would have been only a single charge. Anything of this complexity should have had redundancy and a good margin of safety built into its design. I would expect to hear
many charges go off -- and this noise is unmistakable, multiple shocks in rapid succession. Nothing else sounds like that. The only other alternative, from a mission success standpoint, is to put in a single very large explosive, big enough that precise placement or optimal structural weakening was not a factor. I trust you can see the problem with this approach as well.