9-11 Presentation at NMSR, May 19 2010

AZCat said:
Your assertion is incorrect. The force required to stop the upper block from continuing to accelerate is similar to the force seen by the lower block for thirty years, but the force required to decelerate the upper block and arrest collapse is greater than the historical force.
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That's what I said.
 
ergo said:
That's what I said.
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Ah, I see. It was the juxtaposition of the two in your post that made me think you were claiming the "force equal and opposite the impact force" was the same as the historical force.

Then we can move on and address the part where you claim "It can and would exert a force equal and opposite to the impact force provided by gravity to stop its descent any further past the damaged floors." What do you think this impact force would be, and why are you so sure the lower portion can withstand the impact? At what magnitude of impact do the structural elements composing the lower portion fail?
 
AZCat said:
Then we can move on and address the part where you claim "It can and would exert a force equal and opposite to the impact force provided by gravity to stop its descent any further past the damaged floors." What do you think this impact force would be, and why are you so sure the lower portion can withstand the impact? At what magnitude of impact do the structural elements composing the lower portion fail?
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At the same magnitude that the structural elements composing the upper block would fail.
 
ergo said:
... Downward momentum is easily and quickly arrested by the taller, stronger, more intact lower block for the reasons I outline above.
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Total nonsense. ... get some knowledge on physics, practical knowledge. You sound like that failed video you posted.
 
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Ergo,

You're right. Everything you've said is the absolute truth, and you've finally uncovered the truth about how the towers fell. But the people here on JREF, like me, are just idiots who don't understand basic physics. As a person pretending to be a civil engineer, I want to applaud you for finally pointing out my fraudulent claims of education. Clearly, you are the only intelligent person that has ever visited JREF, and you were instantly able to see through all of our hot air.

Now it's time for you to take the next step. I think you should take your ideas and submit them as a 1 page abstract for the 2011 Architectural Engineering Conference in Oakland, California. Specifically, you'll be submitting to the Structural Systems, Progressive Collapse symposium. Since you might not be familiar with the abstract guidelines, I've created one for you. Please feel free to submit it with your name and your credentials on it. You need give no credit to me or to JREF.


The collapse of the World Trade Center towers on September 11th, 2001 was a great tragedy for the U.S. But what really makes this a tragedy is the conspiracy, directed by the Bush Administration and Larry Silverstein, to hide explosives in the towers and in World Trade Center Tower 7, in order to force the buildings to collapse. Explosives were placed at each floor, timed to explode as the tower collapsed, removing the structural support at each floor before the falling material reached the floor. Explosives were a necessary part of the plan, since without removing the structural support prior to the collapse, the collapsing structure would have been arrested at the first floor. While this theory may contradict the official theory set out by FEMA and NIST as part of the NCSTA Reports (and based on the work of Benzant et al.), a simple analysis of the forces involved proves that this structure, and no other structure built according to modern design codes, will ever collapse.

As the collapse began, much of the material at the collapse initiation zone began to pulverize. This pulverized material exerted less kinetic energy due to a change in the shape of the material. Although an energy analysis of the collapsing upper sections of the towers showed more than 1 GJ of kinetic energy, when the shape and size of the rubble pieces are taken into account, in addition to the material that was ejected upwards and outwards, the actual kinetic energy of the system was less than 1 kJ. By applying Newton's third law to the collapse front of the material, we find that with 1 kJ of energy being directed downward, the lower structure of each tower, which was stronger than the upper structure by a factor of 10 or more, will exert 1 kJ of energy upwards. The summation of the force/energy vectors results in a net 0 acceleration, thereby proving collapse arrest. Building codes are all designed to handle, due to factors of safety, any amount of material to be dropped onto each floor without any damage to the structure below. The amount of material dropped during the collapse of the towers was well under the collapse threshold, which for a building of this size, was over 100 times the actual material dropped.


Ok, feel free to edit and submit, ergo. It's your time to shine!
 
I swear, if I see that in a journal, it better be under the humor section, with a big rolling eyes picture right below it!!
 
ergo said:
Because energy has been expended in crushing those two floors on both the upper and lower blocks. Maybe another pair of floors would go, and maybe more, but it would not keep continuing, because energy is expended each time, and there is no new energy coming into the system. I.e., there are no new "drops" happening.
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Do these floors that "go" just hang in the air?

Did you forget about that pesky gravity again?

I think you also "forgot" that while these floors are "going" the upper block is still moving down and gaining mass.

:o
 
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AZCat said:
And that is?
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Doesn't matter until you state what point you're making. The point I'm making is that the upper and lower blocks are made of the same material (for the most part) and constructed in the same way (for the most part--lower block being a little bit stronger overall), and the impact affects them both similarly. There's nothing more "powerful" about the upper block.
 
ergo said:
Doesn't matter until you state what point you're making. The point I'm making is that the upper and lower blocks are made of the same material (for the most part) and constructed in the same way (for the most part--lower block being a little bit stronger overall), and the impact affects them both similarly. There's nothing more "powerful" about the upper block.
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Except for the fact it's falling.



:rolleyes:
 
ergo said:
Doesn't matter until you state what point you're making. The point I'm making is that the upper and lower blocks are made of the same material (for the most part) and constructed in the same way (for the most part--lower block being a little bit stronger overall), and the impact affects them both similarly. There's nothing more "powerful" about the upper block.
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It does? Care to draw a free body diagram of the impact?
 
You can do a simplified FBD with only 3 forces, ergo....
 
AZCat said:
Why don't you try drawing a free body diagram, then you might see why the two portions would react differently.
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Why don't you apply Newton's Third Law to your picture, and then you might see why the impact affects both upper and lower portions of the building equally.
 
ergo said:
Why don't you apply Newton's Third Law to your picture, and then you might see why the impact affects both upper and lower portions of the building equally.
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Guys, I don't think ergo even knows what a free body diagram is. It's amusing watching him use Newton as some sort of Get out of Jail Free card.
 
ergo said:
Why don't you apply Newton's Third Law to your picture, and then you might see why the impact affects both upper and lower portions of the building equally.
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I think if you go ahead and draw a free body diagram you will find some clarity.
 
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