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So last night I was thinking about the argument that since the towers fell at nearly free-fall speeds, that means that something other than the 2 airplane impacts must be involved.

To me nearly free-fall speeds doesn't seem surprising. I think the reason some find it puzzling is that acceleration under gravity involves nonlinear equations that may seem counter-intuitive. People also find things like compound interest (a tiny change in interest rate can result in huge differences in absolute dollars) hard to intuit because of nonlinearity.

So I started work on a toy simulation to compare free-fall versus the pancaking process where kinetic energy is expended by the falling mass to break free each subsequent floor, and momentum from the falling mass has to be shared with the previously unmoving floors added to its mass.

I did the equations last night, and this morning I was about to code it into Matlab (an engineering programming environment I use) when I decided to first check and see if others had already done this.

I'm glad I did. Here is a paper that does a much better job than I would have.

http://www.911myths.com/WTCREPORT.pdf

To understand this paper I'd say you only need algebra and first year college physics.

The paper clearly demonstrates that:

1) The buildings falling at near free-fall rates is to be expected.
2) The kinetic energy released by the fall was more than enough to shatter all of the concrete into a fine powder.

The author also notes, and allows that it may be controversial, that

3) The asymmetric damage done by the jet impacts alone may have been enough to eventually bring down the towers *even if there had been no fire at all*.

...and more.

It was satisfying to see that the equations in the paper were similar to my own, and the author even cites the same "piston" analogy I used earlier to explain the "squibs" or "explosions" shooting out of the sides of the falling towers.

If you think that physics matters in this debate, this paper is a must read.

-Phil

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Earwicker wrote:Bob your answers seem reasonable enough so i will direct my questions to tuther fella - cwiko:

Do you think it more reasonable to conclude that we have had contact with life from other universes than a part of the intelligence agencies might of had a hand in 9/11?

If so why so?

Yes, Earwicker, I do. I think it's strictly too high of a probability that there is life in other parts of the universe. Couple that with all of the secrecy and hearsay of goings-on at Area 51 and I do believe you've got something happening there.

As far as part of the intelligence agencies having a hand in 9/11, I believe the only hand they had in it was the sheer ignorance, laziness and general discombobulation that prevented them from stopping it from occurring. Of course, it seems to me that Bush himself could be equally blamed for this, but if our FBI & CIA weren't so damn busy investigating a stain on a dress the previous years leading up to 9/11, maybe they'd be more preoccupied with 19 men learning how to fly planes without caring for knowing take-off and landing procedures. Truth be told, I am not entirely sure that our government didn't have something to do with the events of 9/11, it's just that the evidence presented in the videos from the beginning of this thread don't convince me that that's what happened that day.

clocker bob,

I cite a physics paper, and your first criticism is that the website operator, who is *not* the author of the paper, is not a physicist. That's a non-argument.

See, the thing about physics is that it doesn't really matter *who* the author is...let alone the publisher of the paper. The math and the derivation as well as the final results are laid out for anyone to verify for themselves. It's only when someone doesn't show the derivation, but just states the results, that you are forced to wonder about credentials.

The man just explained to you that no significant resistance
was measured in the collapse time. According your crazy Arab, magic fire, and pancake conspiracy theory, the floors had to be broken loose from their anchors and then accelerated from a stop. That should have slowed the rate of collapse - big time.

Did you even read the paper? This is fully addressed. There is a chart that treats the energy used to break each floor loose as a variable parameter, and it shows that over a wide range the result on the fall time is very small...a variation of .5 seconds or so.

'll stick with Hank and all my poorly-credentialed scientists from MIT and other universities. You can have your bad science to support your bad explanations, with your comparisons to radio towers and other flights of whimsy.

Calling it bad science doesn't make it so. I've cited a specific paper. To discredit it you have to show specific reasons.

(It's really a diversionary argument, but does the above mean you actually think you could bolt together steel girders into a single long extension 1365 feet tall and have it stand perfectly straight and stable without cables or other supports? And that a 110 story building can shimmy down a composite vertical girder like a record dropping down the spindle of an old fashioned record player, without doing any damage?)

“[N]o video of either of the WTC collapses shows any sign of stutter between floor collapses,” writes physicist Derrick Grimmer, “which should have been very apparent especially in the first few floors of collapse when the speed of gravitational collapse was small”.

Remember in math class where it wasn't enough to jot down an answer? You had to "show your work".

Well, he doesn't show his work. And that's bad science.

Again, check the equations in the paper. They show why this doesn't happen. Without quantification, the basic reason is the falling mass (30 or so stories worth) represents much more energy than the strength and standing momentum of a single floor. And thats for the first floor drop. Every subsequent floor is overpowered by an increasing amount.

But again, this is shown in the paper, and the retort you cite just pulls an answer out of a hat.

The model makes the critical assumption that the floors get hit and offer no resistance beyond a conservation of momentum calculation.

This is not true. It is either a lie, a stupid error, or perhaps a comment based on an earlier less complete version of the paper. (I am trying to be generous in holding out that last one).

Note especially the end of the first sentence below, the time estimates, and the last sentence. E1 is exactly the resistance they say is missing from the model. And yet, there it is. Quoting from the paper.

We have re-calculated the descent velocity after the impacts on every floor and determined a revised collapse time that now includes the effects of the energy lost in crushing the support structures. Rather than restrict our calculation to one value of E1, say 0.6 * 10**9 J as given in Table 1, we have carried out the calculation with E1 treated as a variable parameter in the range zero to 2.4 * 10**9 J. Some of the key results of these calculations are shown in Figure 2. Based on an assumed value of 0.6 * 10**9 J for E1 we have the following revised estimates for tc:

WTC 1
Previously (E1 = 0) tc = 12.6 sec
Revised (E1 = 0.6 * 10**9 J) tc = 12.8 sec

WTC 2
Previously (E1 = 0) tc = 11.5 sec
Revised (E1 = 0.6 * 10**9 J ) tc = 11.6 sec

Figure 2 shows that tc is quite insensitive to the value selected for E1 up to E1 = 2.0 * 10**9 J. Thus, even if E1 was twice as large as our estimated value of 0.6 * 10**9 J, tc would only increase by about 0.5 seconds, (See additional comment on this case below).

Considerations such as these lead to the conclusion that a relatively large increase in E1 only produces a small increase in the collapse time tc, providing E1 is less than 50 % of the kinetic energy delivered to the floor. Our estimate of E1 places it at 25 % of the initial impact kinetic energy for WTC 1 and 12 % of the impact kinetic energy for WTC 2.

Figure 3 shows how rapidly the ratio E1/Ti, (collapse energy to available kinetic energy), declines from each successive floor collapse. Hence it is not surprising that inclusion of E1 in our momentum transfer theory increases the calculated collapse times by less than 0.5 seconds.

End of quote from paper I cited.

Your quote then says.

More in accord with common sense (sound scientific calculations are nothing more than refined common sense), the enormous pyroclastic dust cloud from each tower’s destruction required tremendous energy, at least ten times the potential energy available from a tower’s elevated mass due to gravity. This phenomenon alone renders the pancake theory nonsense.

and again later

Gravity cannot supply enough energy to turn an estimated 100,00 tons of steel-reinforced concrete in each tower into talcum powder

Again, they don't show their work. They just pull "at least ten times" out of a hat. The cited paper addresses this fully and shows you the math.

Math speaks more loudly than any name or degree your writers claim to have. Science is more than 2 children shouting at each other "is too!", "is not!", "is too!", "is not!".

Unless they show their work there is no reason to think they trump the cited paper.

Unless *you* show something more than quotes from other people who don't show their work and just pull answers out of a hat, there is no reason to think your post trumps the cited paper.

-Phil


(Aside to anyone following along. Again the cited paper is:

http://www.911myths.com/WTCREPORT.pdf

Also, for a more general, less technical, debunking that I think is pretty good, see this article that was noted in another thread.

http://www.popularmechanics.com/science ... 27842.html )

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clocker bob wrote: You're a retard. You didn't read my supporting documents because you're a retard or a CIA plant. I finally got to meet a CIA plant after posting about 9/11 for three months-excellent.

I very much like the cut of your jib, Bob. i have alot of time for your opinions and the research you do but for me you do occasionally overstep the mark.

You don't really think Galanter is a CIA plant do you?
He's been popping on the evolution thread for months before he came over here so that would be a pretty elaborate and convoluted ruse.

Galanter to my mind knows his stuff. I agree I don't think he is being objective about the official story but I don't see him as a closed minded person and any reasonable debate you could have with him is reduced by making claims like this.

He immediately presumes you an utter crack because no one knows better then him that he isn't a CIA plant (unless he is of course - cue Twilight Zone music)

cwiko wrote:Yes, Earwicker, I do. I think it's strictly too high of a probability that there is life in other parts of the universe. Couple that with all of the secrecy and hearsay of goings-on at Area 51 and I do believe you've got something happening there.

So - A - the chances are there is life on other planets somewhere in the unverse.
B - something top secret is going on in Area 51

equals - we have contacted alien life and have used their technology to develop our own

(That's some leap. Maybe Area 51 is secret for, well, some other reason that could be explained by the military's need to keep certain earthly things secret. This seems very much more likely to me.)


Against - A the military needs to keep certain earthly things secret and needs loads of money that could be churned up by a never ending war.
B an event takes place whose explanation is full of contradictions and inconsistencies and whose primary benefactors are certain sectors of the government and the military

equals - its a whole load more likely that there was some military/government complicity in 9/11 than that we have intergalactic space conferences with little green men.

Jesus Wept.

I'm trying to stay focused on the issue of whether one would expect the towers, damaged only by the aircraft, to fall at nearly the rate of free-fall. I think they should and I've cited a very detailed paper that supports that. There are indeed opposing papers, and they are indeed *long winded*, but none offers a quantified analysis using physical laws and mathematics. They are informal appeals to watch the video and use "common sense".

For example, I've read the Jones paper, and I've read the links he supplies as support. With one exception, all of that discussion is not quantified, nor are any mathematical models or other standard scientific methods offered. It's mostly "look at the video" and "one would expect that" and so on.

So Jones may be a scientist, but this paper on this sub-topic (the rate of fall) is not terribly scientific. It appeals mostly to common sense rather than physical laws and mathematical analysis. And when in conflict, common sense is less reliable than established physical laws and mathematics.

(By established physical laws I don't mean something specifically for the towers, I just mean good old physics that applies to everything including the towers).

Jones does mention the conservation of momentum and opines that the standard (airplanes toppled the towers) theory would violate that law. But he doesn't substantiate that claim in any formal or quantified way.

The one exception to all of this is a side reference to this link:

http://janedoe0911.tripod.com/BilliardBalls.html

This paper claims to show that under the standard theory the tower should take about 100 seconds to fall. This is the only reference I can find with sufficient modeling detail to actually critique.

And the critique has to be a harsh one. Because the analysis *assumes* that every time the falling mass goes down one floor, the entire falling mass comes to a full stop, and then starts falling again from a stopped position. (See her case 3).

This assumption is an impossibility. It says that no matter how massive or not the falling portion of the building is, the next floor will always bring it to a full stop, *and* then once stopped the mass plus the new floor will start falling again. It says the 110th floor dropping on the 109th floor, will act the same as 109 floors worth of mass dropping on the first floor.

To see how absurd this is, imagine a glass table that acts in the following way. You drop an anvil on it, and the table fully stops the anvil, but then a split second later the anvil breaks though. Next you take an identical table and drop a BB on it...and it stops the BB, but then the BB breaks through. I'd challenge anyone to build such a table.

This wouldn't have happened if the author had created a proper mathematical model rather than a gee-whiz thought experiment. Or, if the author *had* created a proper mathematization of this model, I'd be able to explain the error in a more technically specific way.

Anyway, I've looked and looked and not found an alternate model for the rate of collapse...meaning a fully worked out model based on established science and mathematics.

The only reasonably complete model is the one in the paper I've cited.
The half-baked billiard balls model that Jones sort-of cites is clearly incomplete (it offers, for example, no real world calculations of kinetic energy) and is conceptually broken.

But clocker bob, if there really is a scientific paper that purports to go toe-to-toe with the one I've cited, I'd really appreciate your pointing it out. I want to see physical laws, equations, and quantified results in real world units.

But I'm afraid it's just not out there.

Of course I have an unfair advantage because I can call on all these high powered physicists and mathematicians hanging out at CIA HQ.

-Phil