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Debunk This

imstellar28 said:
"1. It falls faster than free fall with air resistance because the air is blown out of the floors.
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Nope. Ask yourself, what is blowing the air out of the floors?

Either or both of two things are doing this: the gas released by the detonation charges, or the shrinking of air spaces as the building collapses.

In both cases, what's forcing the air out of the floors is higher pressure inside than outside. (If there were a vacuum inside, then the higher pressure outside would blow air into the floors instead.)

So, the falling structure encounters slightly higher than normal air pressure and therefore higher than normal air resistance.

Respectfully,
Myriad
 
My contribution to this thread is unnecessary, so I have decided to summarise it for everyone...

:words: :words: :words:

:jaw-dropp :eye-poppi :

:words:

:teacher:

:words:

:hit:

:words: :words:

:teacher:

:words:

:con2:

:words:

:nope: :teacher:

:words:

:bwall

:words:

:faint:

:words: :dig: :words:

:deadhorse

:words: :dig: :words:



Carry on...

:popcorn1

-Gumboot
 
imstellar28 said:
I don't see what my education, or the education of the author of the article has to do with forming a reasonable hypotheses and providing iterative evidence/calculation to arrive at a conclusion. If these theories are so wrong, why does the discussion always lead to insults of those proposing them or diverting the argument away from its central focus so as to lose track of what is even being discussed?
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You lack the knowledge to understand his opening statements are wrong. I think if you had more education and experience you may not fall for lies and junk science. (use the quote button on the bottom of each post to add the post contents you want to reply to)

and ER needs to read NIST again, you missed some stuff

and gravy is right, wiki is "never ever ever wrong", but how do you push air out and not leave air behind to push the air out??????? we need to see the air pressure numbers on this, and then we need to tell you with massive objects, air, or lack of air can be neglected for the WTC towers falling and you will still be close to the real numbers and damage seen on 9/11. Funny thing, if you take this junk about vacuum into consideration you have proof there was no explosives used on 9/11; not sure how truthers mess up their own stupid ideas; but they always do it.
 
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Now essentially = Faster than?

Someone needs to update Dictionary.com as well.
 
ERichardson said:
NIST admits that the buildings fell essentially in freefall.
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Yoo-hoo! NIST describes the resistance the falling portion met, and that debris that actually was freefalling hit the ground before the mass of the building, and therefore it wasn't a freefall collapse. Really. :)
 
ERichardson said:
So wikipedia being wrong in other cases means it is wrong now?
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No, the statement being wrong means it's wrong now. I don't think you realize that the blast produced by demolitions charges is very, very small compared to the volume of air in a building, and is highly focused. Please read my previous posts in this thread.
 
Gravy said:
Yoo-hoo! NIST describes the resistance the falling portion met, and that debris that actually was freefalling hit the ground before the mass of the building, and therefore it wasn't a freefall collapse. Really. :)
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So you think NIST was wrong to say the blocks above the impact zone fell essentially in freefall?
 
ERichardson said:
So you think NIST was wrong to say the blocks above the impact zone fell essentially in freefall?
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Please print the entire passage here and you'll see what I was referring to. It's good to keep these things in context, don't you think?
 
ERichardson said:
NIST admits that the buildings fell essentially in freefall.
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So that wouldn't be faster than freefall, for a start.

I think it's bad phrasing on their part and I'm sure they don't mean "with an accleration exactly matching that of freefall". Agreed?

Anyway it's obvious that the buildings are falling somewhat slower because the debris that's expelled falls faster.

Rather than worrying about freefall, or NIST's choice of words, you should demonstrate that the buildings fell faster than they should have done.

Can you do this? With calculations?
 
imstellar28 said:
What is the consensus on this board for the time it took for WTC7 to collapse?
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Consensus? Sorry, we've never voted on this. If you have comments to make, make them and be prepared to back them with evidence.

I STRONGLY recommend that you first use the forum search function before bringing up elementary topics like these. You'll see that these things have been discussed ad nauseum. Then you can address specifics in the NIST report or specific comments we've made. Does that sound reasonable?
 
Well, I got this far in the paper cited in the OP:

Fires were dynamic- they started, moved around, and burned out. Fires wormed their way throughout the building looking for fuel (office materials). Fires did not stay in one place longerthan about 45 minues, and typically did not stay in one placelonger than 30-45 minutes. No fires on a single floor ever covered more than 63% of the floor at any one time, and on average only covered 25% of a floor. The south side area of the building (floors 98-94), where collapse initiated, had the second smallest burn area, 73%. At collapse only 27% of the south side area was burning. Fires peaked during the time period 9:36 to 9:58 a.m., when fires covered a maximum of 37% of the building area (floors 98-94, all building sides), then diminished until the collapse at 10:28 a.m. Only 24% of the building area was on fire when collapse occurred.

Floor 97, the floor where collapse initiated, had no more than 47%of its area on fire at any one time. It only had 13% of its area on fire at thetime of collapse. 13% of the floor never had fire. The other 74% was burned out. Fires on floor 97 did not burn longer than about 45 minutes.Fires were dynamic- they started, moved around, and burned out. Fires wormed their way throughout the building looking for fuel (office materials). Fires did not stay in one place longerthan about 45 minues, and typically did not stay in one placelonger than 30-45 minutes. No fires on a single floor ever covered more than 63% of the floor at any one time, and on average only covered 25% of a floor. The south side area of the building (floors 98-94), where collapse initiated, had the second smallest burn area, 73%. At collapse only 27% of the south side area was burning. Fires peaked during the time period 9:36 to 9:58 a.m., when fires covered a maximum of 37% of the building area (floors 98-94, all building sides), then diminished until the collapse at 10:28 a.m. Only 24% of the building area was on fire when collapse occurred.

Floor 97, the floor where collapse initiated, had no more than 47%of its area on fire at any one time. It only had 13% of its area on fire at thetime of collapse. 13% of the floor never had fire. The other 74% was burned out. Fires on floor 97 did not burn longer than about 45 minutes.
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And so forth, over several preceding and following paragraphs. Essentially, the author is equating fire with visible flame, which in an interior fire is highly misleading. No, fires did not "start, move around, and burn out." What moved around were the air currents that enable individual portions of the fire zone to produce visible flame. It is unlikely that any floor or any significant portion of any floor exhausted its fuel supply before the collapse. With the possible exception of areas near holes where inflowing air currents occurred, it's unlikely that any portion of the fire zone ever stopped increasing in temperature, let alone significantly cooled, before the collapse.

Respectfully,
Myriad
 
ERichardson said:
So you think NIST was wrong to say the blocks above the impact zone fell essentially in freefall?
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I think you should have a look at the NIST FAQ.

6. How could the WTC towers collapse in only 11 seconds (WTC 1) and 9 seconds (WTC 2)—speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?

NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A).

As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:

“… the structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.

Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass.”

In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.

From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.
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