So, it's been almost 18 years and I'm still a 9/11 skeptic... Ehh.

So, it's been almost 18 years and I'm still a 9/11 skeptic... Ehh. — Wallows

I can assure you, 9/11 is a real date. Of course, that date is 9th November.

Yes, tries and wallows to sleep.



It's just an insult to intelligence to assume all three buildings fell due to fires. Yeah, there was a third building...

It's just an insult to intelligence to assume all three buildings fell due to fires. Yeah, there was a third building... — Wallows

https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Mechanics_of_Twin_Towers'_collapse

It wasn't just due to fires. The planes themselves damaged the walls and pillars of the floor(s) they hit and so they couldn't support the floor(s) above. The momentum of the floor(s) above falling down then transferred to the floor below, and the building wasn't designed to resist dynamic loads like that. Weakening by fire plus the ever-increasing tons of falling steel and concrete lead to a collapse.

Wow, so we're actually going to argue over this ...

It's bedtime for me so I'm reluctant to get too excited; but, how did WTC7 collapse at free-fall acceleration?

Make a cup of joe and see this (qualified) analysis of WTC7's free fall collapse:

https://www.ae911truth.org/evidence/free-fall-acceleration

how did WTC7 collapse at free-fall acceleration? — Wallows

It didn't. Part of the collapse was at free-fall acceleration, but not all of it.

https://ws680.nist.gov/publication/get_pdf.cfm?pub_id=861610

The analyses of the video (both the estimation of the instant the roofline began to descend and the calculated velocity and acceleration of a point on the roofline) revealed three distinct stages characterizing the 5.4 seconds of collapse:

• Stage 1 (0 to 1.75 seconds): acceleration less than that of gravity (i.e., slower than free fall).
• Stage 2 (1.75 to 4.0 seconds): gravitational acceleration (free fall)
• Stage 3 (4.0 to 5.4 seconds): decreased acceleration, again less than that of gravity

This analysis showed that the 40 percent longer descent time—compared to the 3.9 second free fall time—was due primarily to Stage 1, which corresponded to the buckling of the exterior columns in the lower stories of the north face. During Stage 2, the north face descended essentially in free fall, indicating negligible support from the structure below. This is consistent with the structural analysis model, which showed the exterior columns buckling and losing their capacity to support the loads from the structure above. In Stage 3, the acceleration decreased as the upper portion of the north face encountered increased resistance from the collapsed structure and the debris pile below.

Part of the collapse was at free-fall acceleration, but not all of it. — Michael

Then explain how that is possible?

It's right there in my quote:

During Stage 2, the north face descended essentially in free fall, indicating negligible support from the structure below. This is consistent with the structural analysis model, which showed the exterior columns buckling and losing their capacity to support the loads from the structure above.

"Negligible support" would still provide resistance. The collapse we see cannot be due to a column failure, or a few column failures, or a sequence of column failures. All 24 interior columns and 58 perimeter columns had to have been removed over the span of eight floors low in the building simultaneously to within a small fraction of a second, and in such a way that the top half of the building remains intact and uncrumpled.

Anyway, take a second to review everything here:

https://www.ae911truth.org/

"Negligible support" would still provide resistance. — Wallows

But a negligible amount which means not enough to make a difference.

If I were to stand in front of a train I would provide negligible resistance, and so the train would carry on through me with no noticeable deceleration.

Are you serious?

Are you serious? — Wallows

Yes.

Are you serious in suggesting that it was a planned demolition or whatever it is 9/11 skeptics believe? Because if it were that there'd be far more evidence than just part of one building collapsing at free fall acceleration for 2.5s. That's an incredible reach.

No, I'm not going to shoot myself in the foot and come off as a loon. 8 floors essentially vanished for 2.5s and the only reason they did was due to what NIST called "progressive failure".

And we haven't even touched on the fact that you would have to blast every 24 interior collums with some incredible heat to weaken them ALL to the point of essentially turning them into Swiss cheese, and this all happened near instantly.

Here's the graph:

Kinda dramatic; but, gets the point across: