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Re: Re: Re: Re: Re: Re: Re: Re: Re: WTC 1/2 Seismic data and Physics
| quote: | Originally posted by shaolin_Z
Intellectual dishonesty is believing in a phenomenon that defies common sense and the laws of physics, or comes incredibly close to that. So please stop accusing me of it. |
no, its intellectually dishonest to compare two completely different structures when its been illustrated time and time again that they are different and incomparable.
| quote: | Originally posted by shaolin_Z
I don't care what kind of explanation a selective group of "experts" offer if it isn't consistent with the laws of physics or comes very close to it. Plus, the scientific aspect is only one aspect to 9-11, you guys have failed to address everything else. And you've failed to address the scientific aspect in any meaningful way, or offer any believable alternative. |
"selective"?? the world's engineers are a selective group of experts? wow, id like to know what constitutes a substantial body of experts by your way of thinking.
| quote: | Originally posted by shaolin_Z
Did you miss my post preceding your's where I responded to colonelcrisp's? |
no, but i am unqualified to debate that. ill leave that up to people like colonel.
| quote: |
Rapid Collapses and Conservation of Momentum and Energy
Jones: “How do the upper floors fall so quickly, then, and still conserve momentum and energy in the collapsing buildings? The contradiction is ignored by FEMA, NIST and 9-11 Commission reports where conservation of energy and momentum and the fall-times were not analyzed. The paradox is easily resolved by the explosive demolition hypothesis, whereby explosives quickly remove lower-floor material including steel support columns and allow near free-fall-speed collapses (Harris, 2000).”
To many people the apparent collapse of the buildings at ‘near free-fall-speed’ is one of the most compelling arguments in favour of the CD theory. However it is also the most easily dealt with on scientific grounds. The fact is that the near free-fall-speed of collapse of buildings in controlled demolition is entirely due to gravity, and not to explosives. The question of course remains, how come that buildings, impeded by their intact lower floors, collapse so fast? (Though of course, this is not a question with any direct relevance to 9/11.) Put this way, the question conveys the essential fact of controlled demolition: that the only floors effectively ‘removed’ from the building are the lowest. (Further charges are placed in the building if and only if it is necessary to guide its fall in a certain way, for example to collapse a building into its footprint.) In a 20-story building, for example, the bottom floor or floors is extensively rigged with explosive, to remove its load-bearing capability. The remaining 18-odd storeys pancake into the region of the destroyed floor, one at a time, raising exactly the same question as to how is it that this process can take place so quickly? The same question applies to conventional demolition, and to the Tower buildings. The difference is that the pancaking occurs high in the Twin Towers (‘top-down pancaking’), and at the base of WTC 7 (‘bottom-up pancaking’). In the usual bottom-up process each floor impedes the process of collapse through its structural rigidity, just as much as one would expect in the top-down processes in the Towers. Although no text-book account is available which might give a simple answer to the issue of the speed of gravitational collapse of buildings, one might draw on the analogy of a hydraulic press compressing, say, a car body shell. The car body shell may seem strong enough to withstand everyday loadings, but, when it takes the hit of a high-powered press, it collapses with astonishing speed. 18 storeys of a big building, moving even rather sedately as they would at the onset of collapse, probably outstrip the forces of even the biggest hydraulic press ever built.
It seems that all the proponents of the CD theory state the case, like Jones above, along the lines: “The paradox is easily resolved by the explosive demolition hypothesis, whereby explosives quickly remove lower-floor material including steel support columns and allow near free-fall-speed collapses.” This is simply unscientific; not corresponding to the reality of how controlled demolition is carried out. Returning to our example of the collapse of a 20-story building, there is simply no need to explode each floor, and such explosions are certainly not the explanation of why buildings fall so fast in controlled demolition. All the calculations produced by the CD theorists, designed to prove their theory, are based on the wrong premise, that explosions accelerate the descent. They don’t: it is purely gravity that does it.
Jones: “We observe that approximately 30 upper floors begin to rotate as a block, to the south and east. They begin to topple over, not fall straight down. The torque due to gravity on this block is enormous, as is its angular momentum. But then – and this I’m still puzzling over – this block turned mostly to powder in mid-air! How can we understand this strange behavior, without explosives?”
Jones seems to believe that a 30-story section of the building was “turned mostly to powder in mid-air,” through the use of explosives. He ignores the fact that large sections of the building, such as this, did fall, and were responsible for destroying or partly destroying other WTC buildings. Although considerable disintegration of the 30-story block was inevitable as it impacted on the rest of the South Tower, the bulk of the pulverisation would have been on impact on the WTC complex. Here is a photo of a large chunk of WTC 2 falling onto WTC 3, which was almost totally destroyed by debris falling from the Towers. This fragment shows a different orientation to the section described by Jones, which suggests that angular momentum was conserved. |
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In every photo and every video, you can see columns far outpacing the collapse of the building. Not only are the columns falling faster than the building but they are also falling faster than the debris cloud which is ALSO falling faster than the building. This proves the buildings fell well below free fall speed. That is, unless the beams had a rocket pointed to the ground.
Just look at any video you like and watch the perimeter columns.
Deceptive videos stop the timer of the fall at 10:09 when only the perimeter column hits the ground and not the building itself. If you notice, the building just finishes disappearing behind the debris cloud which is still about 40 stories high.
Below is a more accurate graphic using a paper written by Dr. Frank Greening which can be found at: http://www.911myths.com/WTCREPORT.pdf
The paper takes the transfer of momentum into account. Like a billiard ball being hit by another on a pool table, each floor transferred its momentum to the next as represented below. The more weight, the less resistance each floor gave. |
| quote: |
The time required to strip off a floor, according to Frank Greening, is a maximum of about 110 milliseconds = 0.110 seconds. It is rather the conservation of momentum that slowed the collapse together with a small additional time for the destruction of each floor.
Below are calculations from a physics blogger...
When I did the calculations, what I got for a thousand feet was about nine seconds- let's see,
d = 1/2at^2
so
t = (2d/a)^1/2
a is 9.8m/s^2 (acceleration of gravity at Earth's surface, according to Wikipedia), [He gives this reference so you can double check him.]
d is 417m (height of the World Trade Center towers, same source)
so
t = (834m/9.8m/s^2)^1/2 = 9.23s
OK, so how fast was it going? Easy enough,
v = at
v = (9.8m/s^2 x 9.23s) = 90.4m/s
So in the following second, it would have fallen about another hundred meters. That's almost a quarter of the height it already fell. And we haven't even made it to eleven seconds yet; it could have fallen more than twice its height in that additional four seconds. If the top fell freely, in 13.23 seconds it would have fallen about two and one-half times as far as it actually did fall in that time. So the collapse was at much less than free-fall rates.
Let's see:
KE = 1/2mv^2
The mass of the towers was about 450 million kg, according to this. Four sources, he has. I think that's pretty definitive. So now we can take the KE of the top floor, and divide by two- that will be the average of the top and bottom floors. Then we'll compare that to the KE of a floor in the middle, and if they're comparable, then we're good to go- take the KE of the top floor and divide by two and multiply by 110 stories. We'll also assume that the mass is evenly divided among the floors, and that they were loaded to perhaps half of their load rating of 100lbs/sqft. That would be
208ft x 208ft = 43,264sqft
50lbs/sqft * 43264sqft = 2,163,200lbs = 981,211kg
additional weight per floor. So the top floor would be
450,000,000 kg / 110 floors = 4,090,909 kg/floor
so the total mass would be
4,090,909 kg + 981,211 kg = 5,072,120 kg/floor
Now, the velocity at impact we figured above was
90.4m/s
so our
KE = (5,072,120kg x (90.4m/s)^2)/2 = 20,725,088,521J
So, divide by 2 and we get
10,362,544,260J
OK, now let's try a floor halfway up:
t = (2d/a)^1/2 = (417/9.8)^1/2 = 6.52s
v = at = 9.8*6.52 = 63.93m/s
KE = (mv^2)/2 = (5,072,120kg x (63.93m/s)^2)/2 = 10,363,863,011J
Hey, look at that! They're almost equal! That means we can just multiply that 10 billion Joules of energy by 110 floors and get the total, to a very good approximation. Let's see now, that's
110 floors * 10,362,544,260J (see, I'm being conservative, took the lower value)
= 1,139,879,868,600J
OK, now how much is 1.1 trillion joules in tons of TNT-equivalent? Let's see, now, a ton of TNT is 4,184,000,000J. So how many tons of TNT is 1,139,879,868,600J?
1,139,879,868,600J / 4,184,000,000J/t = 272t
Now, that's 272 tons of TNT, more or less; five hundred forty one-thousand-pound blockbuster bombs, more or less. That's over a quarter kiloton. We're talking about as much energy as a small nuclear weapon- and we've only calculated the kinetic energy of the falling building. We haven't added in the burning fuel, or the burning paper and cloth and wood and plastic, or the kinetic energy of impact of the plane (which, by the way, would have substantially turned to heat, and been put into the tower by the plane debris, that's another small nuclear weapon-equivalent) and we've got enough heat to melt the entire whole thing.
Remember, we haven't added the energy of four floors of burning wood, plastic, cloth and paper, at- let's be conservative, say half the weight is stuff like that and half is metal, so 25lbs/sqft? And then how about as much energy as the total collapse again, from the plane impact? And what about the energy from the burning fuel? You know, I'm betting we have a kiloton to play with here. I bet we have a twentieth of the energy that turned the entire city of Nagasaki into a flat burning plain with a hundred-foot hole surrounded by a mile of firestorm to work with. - Schneibster edited by Debunking 911
Let me make this clear, I don't assume to know what the ACTUAL fall time was. Anyone telling you they know is lying. The above calculation doesn't say that's the fall time. That was not its purpose. It's only a quick calculation which serves its purpose. To show that the buildings could have fallen within the time it did. It's absurd to suggest one can make simple calculations and know the exact fall time. You need a super computer with weeks of calculation to take into account the office debris, plumbing, ceiling tile etc.. etc... Was it 14 or was it 16? It doesn't matter to the point I'm making, which is the fall times are well within the possibility for normal collapse. Also, the collapse wasn't at free fall as conspiracy theorists suggest.
For more analysis of the building fall times, go to 911myths free fall page.
Please refer to Dr Frank Greening's paper for detailed calculations.
http://www.911myths.com/WTCREPORT.pdf |
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). I'm going to work with WTC1 was 1,368 feet (417 m) high (source: 
