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911 physics for dummies

Corsair 115 said:
Are you saying that you think politics plays a role in determining whether a deserving paper gets published in a scientific journal? What about scientific journals published outside the United States? How would they be subject to American politics?
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Of course politics play into controversial science. Look at the global warming debate. Trans-fat debate. Etc.

American politics is global politics.
 
Gravy said:
It all depends on the question. For instance, the first question requires knowledge of the structure in order to calculate its resistance. The second question is one of elementary physics. The third is based on a false premise.

Why are you only "pretty convinced" that the 9/11 skyscrapers collapsed from damage and fire? Does it give you pause that the 9/11 deniers haven't produced a single paper about the engineering or physics of the collapses that would pass muster in a reputable journal?
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Hi again Gravy.

Sorry, my fault, but there's been a slight misunderstanding. I don't mean to imply I'm only "pretty convinced" the towers weren't imploded. I've never for a moment seriously doubted that 9/11 truth "science" is pure nonsense. What I meant by "pretty sure" is the idea that the basic physics arguments in support of the "natural collapse" are uncontroversial among even basic college level physics professors. Why? Because, not being a science-trained person, I am not sure how complex the physics is, such that all it takes are a few uncontroversial laws or formulas that any physics teacher could immediately see. Hope you see my narrower point!

I guess my main area of interest is about free fall speed. Is it as easy as what's stated on pp2-4 of the Greening Bazant paper? If so, I'll post some of it and ask for help in interpreting it, because it's not easy for me. I fully admit to being a total science ignoramus.

Cheers
 
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Guys, it isn't this hard. Lets skip ahead. Suppose you have concluded in your mind that impact / fire is not the cause. What next? What is the next question?
 
beachnut said:
I said you found just 9/11 truth junk, I was asking how you did it and did not find one real conclusion based in facts.

You need to focus and keep going. I was amazed you collected just truther junk, that is an observation, so?

Yep you have mentioned other work, but you did not seem to learn anything as you said. So? You can carry on, or can you? Either get busy with what you want or get upset, 9/11 is an event, 9/11 truth is a cult.
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I never questioned the truth of Greening's work and so on. My primary questions were: how much of the physics needed to refute the truthers is basic and elementary; and (therefore) would there be a unanimous consensus among even physics professors who aren't specialists in anything. Nothing I've said in anyway shape of form has been an endorsement of the validity of the truth mvt. Sizzler, I'm not in the same position of you. I'm not on any fence. I just desire help in intepreting the science so I don't have to say all the time to truthers "read paper X."


OK, enough complaining. I'll try to be much more specific in my future questions on this thread. I guess I'm surprised that on a forum which I have respect for, one that I consider a great friend, especially in 911 debunking matters, that I would be greeted with this kind of - dare I say - cold reception.

Look, if this forum isn't supposed to be for non-science types to ask questions, let me know and I'll stop posting here !
 
Sizzler said:
Oh my god........

Are people seriously asking questions again????

Oh the humanity.

Grow up.
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Ahem, "Sizzler": Are your posts always as stupid as the one above or was that just an anomaly for you? Frankly, it appears that the former is far more likely than the latter.
 
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Gravy said:
I think the claim there is that the gravity collapses should have taken longer without the building's supports being removed by explosives or somesuch.
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Ah yes, I see now.


Gravy said:
I disagree with that statement. I think it's clear that the exterior columns peeled away as, and after, the collapse wave hit them.
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The collapse wave reaches floor 50, and the exterior columns are pushed outwards at floor 50 by the debris, however rather than just the section at floor 50 peeling out, a 20 floor section of the exterior column grid begins to peel away - extending from floor 50 to floor 30. The exterior columns are now peeling away 20 floors ahead of the collapse wave.

-Gumboot
 
First, let us review the basic argument (Baˇzant 2001; Baˇzant and Zhou 2002). After a drop
through at least the height h of one story heated by fire (stage 3 in Fig. 1 top), the mass
m of the upper part of each tower has lost enormous gravitational energy, equal to mgh (g
= gravity acceleration). Because the energy dissipation by buckling of the hot columns must
have been negligible by comparison, most of this energy must have been converted into kinetic
energy K = mv2/2 of the upper part of tower, moving at velocity v. Calculation of energy Wc
dissipated by the crushing of all columns of the underlying (cold and intact) story (Baˇzant and
Zhou 2002) showed that, approximately, the kinetic energy of impact K > 8.4 Wc.
In calculating Wc, it was noted that, in inelastic buckling, the inelastic deformation must
localize into inelastic hinges (Baˇzant and Cedolin 2003, sec. 7.10)). To obtain an upper bound
on Wc, the local buckling of flanges and webs, as well as possible steel fracture, was neglected
(which means that the ratio K/Wc was likely higher than 8.4). When the subsequent stories
are getting crushed, the loss mgh of gravitational energy per story exceeds Wc that by an ever
increasing margin, and so the velocity v of the upper part must increase from one story to the
next. This is the basic characteristic of progressive collapse, well known from many previous
disasters with causes other than fire (internal or external explosions, earthquake, lapses in
quality control; see, e.g., Levy and Salvadori 1992; Baˇzant and Verdure 2007).
Merely to get convinced of the inevitability of gravity driven progressive collapse, further
analysis is, for a structural engineer, superfluous.
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That's from p. 2 of the Greening Bazant paper.

Specific question: is that all the physics one needs in order to show the possibility of global collapse ?

Specific question: If I went and handed this excerpt to my local physics professor, would he accept it as basic, uncontroversial proof of this?

Are these silly, worthless question?
 
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Sizzler said:
:boggled:
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I can only take that as an admission on your part that, yes, your post was stupid (which it clearly was), and I have no reason to think that your subsequent posts were any less stupid unless and until you provide evidence to the contrary (which you have failed to do to date).
 
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chris lz said:
That's from p. 2 of the Greening Bazant paper.

Specific question: is that all the physics one needs in order to show the possibility of global collapse ?

Specific question: If I went and handed this excerpt to my local physics professor, would he accept it as basic, uncontroversial proof of this?
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Your physics professor would need to be versed in structural engineering to be able to pass judgment on Bazant's papers. However, that professor would easily be able to understand #1 and #10 in NIST's latest FAQ. Still, to declare the calculations correct, he'd need to verify that the masses and strengths of connections are correctly stated by NIST.
 
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Sizzler said:
Of course politics play into controversial science. Look at the global warming debate. Trans-fat debate. Etc.

American politics is global politics.
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Are you saying that the scientific community would only publish papers on global warming which complied with the Bush admins stance?

I'd be interested to see proof of this given that for many years the Bush admin denied climate change was happening, then agreed that it was happening but that it was nothing to do with us, and only recently have they accepted the tenets of AGW. And yet during this time scientific publications were on the whole taking a very different stance to that of the US Government.

You think professionals and academics would shy away from supporting an engineering paper which supported the CD hypothesis if it was credible?
 
chris lz said:
That's from p. 2 of the Greening Bazant paper.

Specific question: is that all the physics one needs in order to show the possibility of global collapse ?

Specific question: If I went and handed this excerpt to my local physics professor, would he accept it as basic, uncontroversial proof of this?

Are these silly, worthless question?
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Those are great questions, and I would go to a physics professor if he will take the time.
 
beachnut said:
Those are great questions, and I would go to a physics professor if he will take the time.
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I very much have been planning to do that. The reason I came here first is to try and narrow down the specific arguments/calculations to be evaluated. I don't want to walk in to some professor's office, throw a bunch of science papers at him and say, "read." A scientific ignoramous I may be. But a truther, or one who only collects junk I'm not. Please don't confuse me with Sizzler. I'm just trying to get a feel for how much one has to know to be the master of 9/11 physics. I'm as passionately against "9/11 truth" as you or Gravy. Sorry if I somehow conveyed otherwise.

Thanks
 
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Hokulele said:
And this statement pretty much describes why you are facing the hostility in this thread. I know the search engine on this forum sucks dead bears (unless you are particularly Google-enlightened), but the information really is there.
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OK, all I'm really saying is, I've been reading about 9/11 truth and reading the debunking claims for years now. What I'm seeking is not new information, but a more layman-oriented distillation of the papers I've been mentioning. The stuff i read is either very technical on the one hand, or too watered down on the other. Anyone can say "the experts say." And science writers are very good at going above the heads of the science-challenged. I think it would be hugely helpful for the debunkers like me to have at their disposal something a little more solid and irrefutable than "no peer review paper exists," but not so technical that I have to go running to a physics professor to understand and accept that the collapse model is something anyone can come to understand, and based on completely uncontroversial physics. If you'll notice, such papers written with that nice blend of very detailed physics, and yet distilled for a lay audience unfamiliar with most of the principles being utilized, are far and few. At least I haven't found one yet.
 
uk_dave said:
Are you saying that the scientific community would only publish papers on global warming which complied with the Bush admins stance?

I'd be interested to see proof of this given that for many years the Bush admin denied climate change was happening, then agreed that it was happening but that it was nothing to do with us, and only recently have they accepted the tenets of AGW. And yet during this time scientific publications were on the whole taking a very different stance to that of the US Government.

You think professionals and academics would shy away from supporting an engineering paper which supported the CD hypothesis if it was credible?
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You make a good point with the global warming.

Before I can answer your question. Can you answer this one:

Who owns various engineering journals? (I don't know)
 
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