The 9/11 Collapse Theory discussion thread

Thanks for the message, siamdave. I'm going to think about this for a bit, but currently I don't see how it matters whether it is a stack of thimbles supporting dinner plates, a brick wall, or a lattice of two-storey metal rods. The same "(1) failure near the impact, (2) those above falling, (3) those just beneath unable to halt the impact, and (4) those further beneath also unable to halt the impact" mechanisim seems like it could apply. 

jas, what was the meant to show?

Fidel wrote:

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It's the high end of the tilted floor at the exact moment when the other end, the lowest end, makes contact with the lower block after an unimpeded 3 metre free fall that takes 0.78 seconds according to Garcia. What we're talking about is the very bottom part of the upper block, or "part C" according to Bazant's terminology.

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And then you divide by the velocity right before impact to get the time it takes for the upper block to travel through that vertical distance.

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Griscom is talking about the exact same "delta t" Garcia arbitrarily assumes a value for. Δt is merely a variable term in Garcia's force balance equation. It's a time value for the duration of impact. Even your hammer and dinner plate example will have a duration of impact. ie. dt will be shorter when hammer face makes perfect face-to-face contact with the dinner plate and longer time duration when hammer face meets dinner plate any angle and . It's a force vector, and yes it has momentum. In the graph below, linear impulse is represented by the integral, ∫F.dt. Delta-t is represented by the area under the force vs time curve. I don't know how else to explain this to you without making a fuckin' video tutorial.

[IMG]http://img.photobucket.com/albums/v697/rabblerabble/Capture-39.gif[/IMG]

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My Δt and Garcia's Δt and Griscom's Δt are all the same mathematical expression, and you're the oddball orange. How do you like those apples?

And if you ever run into the babbler who goes by [url=http://rabble.ca/babble/humanities-science/nist-911-sussudio-science-tru..., maybe you can explain it to him. Because he was hung up on the exact same detail regarding Garcia's proof by intimidation Counterpunch essay.

Griscom's delta-t and Garcia's delta-t seem to tb ethe same. Yours is not. Please note that Griscom and Garcia's definitions both involve a change in the velocity during a transfer of momentum. Your right angle calculation and the subsequent calculation assume a constant velocity and do not mention momentum at all.

jas wrote:

The only evidence I might have of this is Bazant's own admission as to what it was he was trying to explain. When he saw the buildings collapse, and he wrote his first paper two days later, was he asking himself, "what could possibly have allowed the buildings to descend at that speed?" or did he ask himself, "how can gravitation explain this speed and manner of collapse?". Since he entertains no other theories (at least not until others raise them) we can assume that it was something more like the second question that motivated him. Therefore, he finds a calculation that fits the collapse time.

I only wish I understood the math enough to see how he explains how his upper blocks crush through 80 - 90 storeys of concrete and structural steel at a speed that is 1- 4 seconds faster than free fall--oh, wait a minute. He doesn't, does he? He only provides the equation for the collapse initiation--but I do trust the work that other members of the science community have provided to evaluate that.

I think the question Bazant asked himself was "Can gravity explain the speed and manner of collapse?". The answer is yes.

He does entertain other theories, by the way. Including controlled demolition. He shows why they would be highly improbable or contradict the data. But since controlled demolition is not the topic of discussion, we can look at them in another thread.

And you are incorrect about Bazant providing only the equation for the collapse initiation. He provides the math for the entire collapse. I find it somewhat ironic that in this erroneous statement of yours you tacitly admit that you have not even read Bazant's paper to see if the math is there, and you admit that you would not be able to understand it even if you did read it, and yet you feel justified in claiming that Bazant's math is wrong.

jas wrote:

Here is another video of WTC1

http://www.plaguepuppy.net/public_html/video%20archive/Shaking%20before%...

that shows more clearly that it is the upper block disintegrating before the lower block begins to fall. I hold my cursor icon at the last level of damaged floor (see the tiny line of windows dotted with orange fire that we also see in our above gif) so I have a steady point from which to gauge the shortening of the upper block before it is obscured by the dust clouds. We see that dotted line of orange fire stay in place and turn into large bursts of flame as the collapse progresses.

We also see the antenna tilt over, suggesting complete disintegration.

I am unable to watch this movie as I am expected to download it. Do you have a youtube link tothis movie that I can watch later?

jas wrote:

It's elementary that it is. It is crushing itself on the intact building below. If there was no intact building below, if there was no force pushing up, we would see the upper block fall intact, through air, as it were.

In this animated gif, we see the upper block fall partially through the impact zone. It never hits the lower block of storeys. The upper block does fall intact. What you see disintegrating is the exterior wall of the impact zone. The structure in this area has already collapsed, and so the exterior wall, like the upper block, is falling down.

jas wrote:

The columns "failing" is from the crushing of the floors above the impact zone is it not? The impact zone is within the upper block, as is shown in the photo.

No, the failing columns are in the impact zone. And no, the impact zone is below the upper block.

jas wrote:

That's fine. So now you are saying that everything above the red line is the impact zone. That confirms my point that the stress caused by the descent of the upper block is being resisted by the intact building below.

Everything above the static red line is either the impact zone or the upper block. And I do not confirms you point about stress.

jas wrote:

pants wrote:

Since the upper block began to fall as a result of the failure of the remaining structure,

Um, no... it is already falling into the impact zone first.

Quote:

... there would have been no structural member that was still capable of transmitting stress to the upper block, or from the upper block to the lower block.

It is clear from the picture and from the video I post above that the intact building below is absorbing the impact of the descending upper block.

The upper block of storeys falls into the impact zone because it is being held above the impact zone by the the structure in the impact zone, and then the structure of the impact zone fails. When the structure fails, the upper block falls into the impact zone. During this fall, there is no structure holding it up. There is no structure connecting the upper block to the lower block. Therefore there is no stress being transmitted between the upper block and lower block. It is not until the upper block impacts against the lower block of storeys that any stress is transmitted to the lower block.

give it up, pants.

The video does not require download. I watched it just fine on my various dubious connections.

Closing.