Including crush-down and crush-up

http://youthfulindiscretions.com/vid/911/E...fter%20Plan.avi

And that sound, is that to be expected in a gravitational collapse ?

There is also a CNN version of this Mark Heath video, that one is edited and the sound is damped.

Start JREF mode

- A clip with not much sound ==> Did you notice that there is totally no sound during the collapse, no firecrackers

- A clip with tremendous sound ==> Do you expect that a collapse of 250000000 kg mass makes no sound

End JREF mode

We've had the freefallers, the towers didn't start with an acceleration equal to g, but (2/3)g for wtc1 and (3/4)g for wtc2. But this relative long "crush-up" is inconsistent with the model IMO. The crush-up should be in the order of a second because the crush-down ends with a velocity about 50 m/s

Better let the 9/11 Commission know it took 40 seconds because they report it only took 12.

They report it took 10.

I don't understand the thread title or for that matter, it's purpose, especially in how it pertains to your initial post einsteen where you make no clear reference to 40 seconds?

Are you claiming 40 seconds or mocking 40 seconds?

Not sure where your coming from on this one?

I've been extremely busy so maybe it's just me?

MM

It was due to a physorg discussion in which David B. Benson mentioned the Dr Mark Heath video and he said that the crush-up took 5 seconds. I rejected that because if you use a model in which the top block stays (more or less) intact during the crush-down then that block reaches ground zero with about 50 m/s, the crush-up could only take 1 second for wtc1 and 2-3 seconds for wtc2.

From video observation it is clear that the collapse is fast, the ejected mass reaches ground zero quickly because it falls in air, those ejected panels are the ones that NIST used to estimate a collapse time. that was resp 9 and 11 seconds. They don't say anything about the collapse time of the demolition zone. Therefore Greening came with his paper and now the leading papers are the Bazant papers using the same model, but not discrete but continuous solving complex differential equations. There is a lot of confusion about that collapse time. It could indeed be 15 seconds for the crush down, the crush-up (when the block hits the ground and caves in) could not take really much more time. Assume you implode that top block like a controlled demolition from the bottom it would be a normal near free fall time, but now (using the model) it will also be an implosion but then a one that starts with about 50 m/s, that will be a fast one!

The thing that I don't understand is how to interpret the 40 seconds sound in the dramatic video. We observe a rapid collapse but why does that sound last at least 40 seconds ?? I have no idea. If the sound is related with the crush-down & crush-up then the model should be thrown in the recycle bin, because the model cannot explain that.

I'm not sure about this, but I would (at the current moment) say that the collapse has ended and there are still things exploding in the rubble.

I bring this on top. I think this is really an important video. I was wondering what the opinion here is about this video. Let's look at it from a total gravity driven point of view. Let's assume that floors are able to pancake/funnel/wedge and a portion of the core is still standing, could it be that when those also finally fail it takes that amount of time? I then have totally no idea how to interpret this video.

I find your uncertainty about settle time quite insightful and honest. ;-)

There were spires! Both towers!

And they persisted for a short while, but definitely for such a period of time that the nature that any work or claim that even pretends to be modelled after or applicable to the event, must consider when the entire buildings mass settled.

Yet for WTC North and South Tower how is that possible? Because there was a moment when the spires stood with evident support but not necessarily full connectivity from below, any total fall timing OR single-equation approach for crush down energy is moot. Because it does not apply to the event.

Now if I was hootin' and hollerin' about someting reaching a few x feet into the sky, or pointing to the five or six stories of ruin and saying "some of this is higher than the other" you could hoot me clear out of the hall.

But we're talking about the spine of the buildings. Some 43FL in height, with some elements stretching to ~50-60FL.

If a single top-to-bottom fall (Bazant's paper) cannot encompass the entire event, it is not applicable. Moot. Non sequitir. And any pathway of argument that seeks to either validate or discredit it is at best impossible, at worst a tragic waste of time. Because it is simply not applicable.

The spires also blow everything anyone ever said about 'free fall' into the unapplicable circular file too.

The natural human tendency I have observed when I mention things like this has been denial through disinterest, I usually get no reply at all. Or some shrug and no general interest, it flows out and aside and away. I don't know why, because it's uncomfortable maybe.

But Bazant and free fall timing both -- only apply (in the end where it really matters) to structures that 'settle all at once'. NO ONE HAS EVER tried to bring a 'free fall' argument into any situation where there is any degree of variation to the 'settle'. No one in their right mind would apply these arguments to something that bounces (unless the bounce is in the equation) and certainly not something with multiple 'settles'.

And (just saying hypothetically) to 'model' the crush-down sans spires... then go ahead and consider the spires' fall as if it were its own little energy event would be the saddest band-aid ever stuck. Because it would be further traveling down the road of inapplicability.

And it's not just a matter of 'leaving no stone unturned' either.

Fixation on free-fall and energy-fall equations actually divert attention away from the spires. It allows diversion from the keenest edge of the evidential Razor. The event itself, as it happened. By allowing people to say, someone will get back to that 'part' later if at all. In terms of people-time-urgency this is like a police detective shrugging and letting cops walk all over a crime scene before it is photographed, with the comment, "we'll get everyone's prints later and sort it out."

Regards the Towers, I believe the spires were trying to tell us something. Why are they tend to be a seldom if ever mentioned aspect?

___
My two cents. Sorry if I'm essentially impolite in my directness, it's just me. Frustrated a bit.

You used a lot of words but I failed to discern what it was you actually wished to say hocus pocus?

MM

he's saying both sides are wrong, I think.

But re: freefall vs. settled building etc... I thin kthe main point of quoting "free-fall" in arguments is that basically, "No part of the upper structure could have falling down towards the ground, even if it hit something and took seconds to setting on the ground, at or near anything even resembling that of a free-fall in air, since the lower supports and structure were alleged to not have been damaged by the planes"

what you are doing is more clearly defining what happened as it fell, but not really debunking the core of the argument that free-fall, or anything resembling such a thing, could have happened to any large portion of the structure. If a slab of concrete fell outside of the footprint, then of course it would free-fall, but the materials that did not fall outside of the footprint, should have met such massive resistence, that even if it fell totally and as NIST describes, "Globally", it should never have happened at such great speeds/short duration.