9/11 Physics from Non-Experts

jhunter1163 said:
Where's R. Mackey when you really need him?
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Yes indeed.
I found a text book, and i am going over this. It's been awhile, but i need to take limits. We have a very large mass, with a very large kinetic energy. It's been 8 years since i did this stuff. I can't believe I am doing your homework Greg.
 
3bodyproblem said:
Yes indeed.
I found a text book, and i am going over this. It's been awhile, but i need to take limits. We have a very large mass, with a very large kinetic energy. It's been 8 years since i did this stuff. I can't believe I am doing your homework Greg.
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If your homework is proving that an object gets magically resistant to a destructive force because it is moving at 8.6 m/s, you might as well give up. Is there anyone here I can have a serious discussion with?
 
GregoryUrich said:
If your homework is proving that an object gets magically resistant to a destructive force because it is moving at 8.6 m/s, you might as well give up. Is there anyone here I can have a serious discussion with?
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You're a little arrogant thing, aren't you?
 
GregoryUrich said:
If your homework is proving that an object gets magically resistant to a destructive force because it is moving at 8.6 m/s, you might as well give up. Is there anyone here I can have a serious discussion with?
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Both the impulse of deformation and the impulse of restitution are functions of the particles velocity and mass. You have a larger mass (the upper section) moving at a velocity much greater than the smaller mass (lower floor), the result is less deformation in the larger, faster mass.
 
3bodyproblem said:
Geesh, It's what you just Wiki'd and quoted, that's why i said Google it.
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I Wikied coefficient of restitution.

Only got 9 hits on google for "Newton's collision rule). It would seem that Mosterman and Wasfy are the only people in the world that use this term besides you.
 
3bodyproblem said:
Both the impulse of deformation and the impulse of restitution are functions of the particles velocity and mass. You have a larger mass (the upper section) moving at a velocity much greater than the smaller mass (lower floor), the result is less deformation in the larger, faster mass.
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So the entire mass of the top section counts but the entire mass of the bottom section doesn't count.

Real life collision:

http://www.youtube.com/watch?v=bMOUVPZh9wA

Time to throw in the towel.
 
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Now you sound like NetForce=0 boy. The mass of the entire building isn't the question Greg, only the floors.
Are you seriously suggesting I can't shoot a spring through a window? The spring with a high velocity is modeled as a solid object for a reason. The same thing applies to a giant spring crushing a smaller spring. Like the ones that came before you, you easily forget orders of magnitude.
 
GregoryUrich said:
I Wikied coefficient of restitution.

Only got 9 hits on google for "Newton's collision rule). It would seem that Mosterman and Wasfy are the only people in the world that use this term besides you.
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Newton's collision rule is:

the coefficient of restitution = - (velocity of separation)/(velocity of approach)

It is also: impulse of restitution/ impulse of deformation
 
3bodyproblem said:
Now you sound like NetForce=0 boy. The mass of the entire building isn't the question Greg, only the floors.
Are you seriously suggesting I can't shoot a spring through a window? The spring with a high velocity is modeled as a solid object for a reason. The same thing applies to a giant spring crushing a smaller spring. Like the ones that came before you, you easily forget orders of magnitude.
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No, it's a little spring falling on a big spring. If you can't get this, we don't have much to talk about.
 
GregoryUrich said:
No, it's a little spring falling on a big spring. If you can't get this, we don't have much to talk about.
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Yes poor example, but the principle still holds. You still have a spring with kinetic energy colliding with a stationary spring.
 
GregoryUrich said:
In this case I'm damn sure.
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Well, the majority of experts in relevant fields disagree with you. What I mean is since that is the case, unless you are 100% totally sure that your opinion trumps their opinion, you are just exhibiting some serious hubris.
 
twinstead said:
Well, the majority of experts in relevant fields disagree with you. What I mean is since that is the case, unless you are 100% totally sure that your opinion trumps their opinion, you are just exhibiting some serious hubris.
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I'm not sure which case you are talking about. I'm not sure you are either.
 
GregoryUrich said:
I'm not sure which case you are talking about. I'm not sure you are either.
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Quit being coy. I'm a layman, so your figures have no effect. You may very well be totally right. My question is why on God's Green Earth do so many experts disagree with you?
 
GregoryUrich said:
So the entire mass of the top section counts but the entire mass of the bottom section doesn't count.

Real life collision:

http://www.youtube.com/watch?v=bMOUVPZh9wA

Time to throw in the towel.
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Hey! He got it right!
Only the mass in collision counts. Good job! The rest of the mass of the lower part of the building is separated from the collision by springs, also know as columns and trusses.

Collision happens between all the mass falling with one floor at a time
 
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gumboot said:
Like you were damn sure that a PC weighs 26lbs?

-Gumboot
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Did I say I was damn sure?

I just gave that as a value to help visualize office furnishings. I didn't hear you arguing about the fact that I put 80,000 people and their computers in the building (I was tying to exaggerate). Since that is more than three times as many people as actually worked there, I had 80lbs of PCs per actual person. Or did you miss that?
 
rwguinn said:
Hey! He got it right!
Only the mass in collision counts. Good job! The rest of the mass of the lower part of the building is separated from the collision by springs, also know as columns and trusses.

Collision happens between all the mass falling with one floor at a time
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I thought you were one of the brighter ones here, and you go and let me down.
 
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