Science a GoGo's Home Page Forums General Discussion Physics Forum Understanding Building Collapse Physics

I am having trouble understanding a building collapse. According to NIST, on 9/11 WTC7 collapsed after fire weakened its structural steel. They have however admitted that WTC7 fell for 2.25 seconds at free fall. (http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR%201A.pdf) However isn't all the gravitational potential energy of the building used up in attaining free fall? Why did the structure in the way not slow the collapse in any way during this period? Fire can't blow out 8 stories of structure simultaneously and continuously floor by floor. Energy and momentum don't seem to be conserved here which is a violation of the laws of physics. Can anyone please explain how I am wrong here?

It fell in 3 stages




Potential energy is expended regardless of whether the building is in free fall.


Because the support structures had previously buckled (in stage 1). The structures DID slow the collapse prior to buckling.



Fire didn't blow it out. Fire weakened the supports and the stress from above finally caused those supports to buckle.

First, what evidence is there that buckling even occurred?
Second, supposing buckling did occur, exactly how did this buckling cause 8 stories of structure to be completely removed to allow the free fall period? How did this buckling miraculously occur simultaneously all throughout every floor for eight stories?

cmatrix,

Are you trying to understand the physics or justify your preconceived opinion?

Are you trying to redirect attention away from your inability to answer these direct questions?

Your questions demonstrate that you don't understand the physics, but you clearly have made your mind up about it.

The question demonstrates a desire for an answer or proof of an idea, and failure to answer the question with an accusation toward the person asking the question demonstrates an attitude toward the question and the person asking the question. Berating someone for asking a question is a smokescreen.

People ask questions for multiple reasons. If they don't understand something, they might ask a question. If they want to lure someone into a debate, they might ask a question. If they want to proselytize, they might ask a question.

I stated a fact. His previous posts indicated clearly that he wasn't very knowledgeable of physics. I can give a specific example where his question was just nonsense. And that's perfectly fine if he's really aware that he doesn't understand the physics and really wants to develop that understanding.

But there's more. The follow on question indicate that he's already made his mind up about this - prior to understand the physics.

This is a reasonable - though not certain - inference based on the transactions in this thread. I'm asking, before I proceed any further, whether he's actually looking for understanding, in which case I'm happy to try to help to the extent I can. I'm always eager to help people who want to understand and to hone my own understanding.

But if he wants to debate or he just wants to argue about something he doesn't understand, then I'm really, *really* busy right now and maybe someone who is more knowledgeable and has more free time will be better suited to engage him.

If... So far a question has been asked and you made an accusation toward the question which reveals the assumption you made. He then made his reply. Is this the beginning of a debate, and who lured who to what response?
Isn't that the way it goes? Without the experience of something other than ones own beliefs one clings to their suspicions and their own ideas until they can be replaced with something to supersede their own ideas. The show me the facts and proof approach. Kinda like a scientist in his approach to a spiritualist.
This is reasonable -though not certain- inference based on the transactions in this thread... I missed the part about you asking if he wants more understanding by accusing him of already making up his mind. So bearing that thought in mind are you asking now or assuming you already asked when making the accusation?
That would be reasonable assuming you are really really busy.

"Kinda like a scientist in his approach to a spiritualist."

Well, at least you acknowledge that the two sets are different.

Maybe you can explain it to him.

I think a spiritualist is much more capable of integrating the experience of spirit into the physical sciences than a material scientist without the experience of spirit is willing to accept spirit. Without any experience of something that cannot be proved by the instruments created from the lack of experience of spirit, I believe that the scientist must separate the idea of personal experience and non experience into two separate sets of ideas. Unfortunately ego often intrudes into the domain of objectivity and creates prejudice, and then emotions tend to further divide people into sets and keep them from communicating or co-operating.

I'm going to assume this is a common understanding and that I won't have to explain this to him and that is included in his approach.

I was suggesting that you could explain the physics to him - preferably without using the usual vacuous language to ejac ... project your ego all over him.

I wouldn't think of taking any opportunity away from you to rise above the usual display of irritation and judgment. Perhaps you could answer his question rather than to make excuses by pointing out someones inability to meet your expectations in beliefs and prejudice.

Ah! I see! Despite not ever having made a single comment that was relevant to actual science, you could indeed answer this question if you chose to, but instead, you think that *I* should answer it for him, despite the fact that he appears to have made up his mind and isn't actually interested in an answer. I see.

Naw. My time is, of course, unimportant, but what is important is *HIS* time. It's apparent you know vastly more about the physics involved than I do and that he deserves your infinitely more insightful explanation. Of course you're much more open-minded and with your spiritualist insights, it's clear you stand a better chance of correcting or confirming his understanding.
Also I wouldn't want my ego making a smoke smokescreen and all that.

Please, I beg you to illuminate this thread with your transcendent and perfect insight.

Interesting discussion but let's summarize the NIST explanation:

The claim was made that the free fall period was enabled by the buckling from stage one. The only way this could be true is if this miraculous buckling affected every one of the 58 perimeter columns and 25 massive core columns simultaneously all throughout every floor for eight stories. IOW the buckling would have to have caused 8 stories of resisting structure to be effectively removed to allow the free fall period.

The NIST explanation does indeed appear to violate the conservation laws and is therefore false.

"...appear to..."? So it 'appears' false to you, based on your interpretation of the data of which you are aware. Very reasonable. But it "is therefore false" - not at all a logical conclusion.

FF definitely has taken an interest, considering he said he was really really busy and had no time for arguments or debates. I really really appreciate him making such a compromise.

Oh, if only you could.

And the actual scientific proof for the assumption that he has made up his mind is?....

relevant statement.

Scientifically speaking of course. You have invested an interest in him, his time and know what is best for him?
No, I left that part to you which you don't seem to want to focus on as much as his time and what I can do or can't do. Is this a scientific interest or an emotional one?

No, just seeking some of your scientific insights to your interactions with him and others in this environment, your hostility toward non-scientific principals and the lack of definition regarding what science is, and in the discussion of science your lack of faith in people.
How would you recognize perfect insight, scientifically?

Thanks for making time to enter into such a debate. I know how really really busy you are.

Good point redewenur. Let me correct my statement then:

The NIST explanation clearly does in fact violate the conservation laws and is therefore false. Anyone who disagrees with this obvious conclusion needs to explain how fire can miraculously remove 8 stories of resisting structure floor by floor simultaneously and continuously to achieve free fall for 2.25 seconds. The science of fire is very well known. Normal office fire damage to steel is gradual not instantaneous like damage resulting from timed well-placed explosives or thermitics.

In science the simplest explanation that best explains the facts should prevail. Crackpot pseudoscience OTOH involves overly complex physics-defying explanations that produce far more questions than answers. 9/11 was not only a massive human tragedy but a brutal assault on science as well.

The question is what are you all going to do? Cover in fear or get off your backside and do something about it?

building 7 was demolished.

http://www.youtube.com/watch?v=j2q2mD2HaKA&feature=related

just because NIST doesnt recognize the admission in the above video only sudgest the fear flowing from the era or
administration.

as I see it knowing that the building housed the secret service , the cia , the sec , fema , etc...etc... the data , records and most likely top secret intelligence was in danger of being compromised and if the fire dept didnt bring it down then Im almost sure that someone would have.

The big problem is Paul that a demolition of that scale requires several months to plan. They only had 5 hours.