Physics of 9/11...

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posted on Aug, 8 2010 @ 07:42 PM
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reply to post by Joey Canoli
 


You expect us to find your knowledge of physics credible when you first try to explain it away with an F=ma approach, see that almost your entire post is proven incorrect, so change tact and attempt to prove your point with momentum vectors?


You've asked how the upper part could apply a net force of greater than 1.0W, when gravity cannot be greater than 1g.

Momentum is the answer.


I said gravity cannot apply a force greater than 1.0W downwards to the upper block, therefore the net force acting on the block in the downwards direction should be less than 1.0W, as gravity is the only downwards force acting on the block.

Your internet physics education has obviously not provided you with a sufficient understanding of momentum, as I will explain.

F=ma, therefore we both agree that for there to be an acceleration of the mass there must be an imbalance of forces resulting in some net force downwards (the direction of the acceleration).

You claim:


Net force from the descending part was 1.7W.


With 1.0W being provided by gravity and 0.7W of downwards force being provided by momentum. Only, here is (one of) your mistake(s):

Momentum is not a force!

Force is the push or pull applied to an object to change its momentum. Without a change in momentum there is no force. It is just another way of stating what I have been saying the entire time in this thread, that if there was a deceleration (negative change in momentum), this would have meant large loads were being applied to the lower structure. As the top section continuously accelerates for most of the collapse it is gaining momentum (positive change in momentum), this ALL comes from the downwards gravitational force being applied to the top section.

What you are trying to tell us is that momentum is a force which is acting on the upper section to accelerate it. I'm saying that gravity is providing the only downwards force acting on the upper section. Let's say hypothetically that the leaning top section continued to lean over and fell off the tower, meaning the only thing between it and the ground was air. As gravity is the only downwards force acting on it, the highest acceleration it could achieve would be near free-fall (there would be some wind resistance), ie 1.0W due to gravity acting downwards minus about 0.1W (this would change throughout the fall as velocity changed) upwards wind resistance, resulting in a net 0.9W downwards. If momentum was indeed a downwards force acting on the upper section helping it to accelerate as you say it is, then in this scenario we would have the 1.0W downwards from gravity plus some downwards momentum (you have given 0.7W). This would result in a net downwards force greater than its weight and greater than free fall accelerations.

Another error which you have made (but is less relevant because your entire method of using momentum as an an accelerating force is wrong) is that you have said that the net force is 0.7W downwards to give a 70% free fall acceleration, but then stated the momentum equation (I'm not sure what for, you didn't use it and it's not as if I don't know how momentum is calculated) P=mv, where v is velocity. So if velocity increases momentum obviously increases, but you have given us a momentum "force" which is constant throughout the constant acceleration. With constant acceleration the momentum would constantly increase.


Kids understand momentum.


Maybe you should consult with some children and have them check your work before posting here then.

Try again Joey.







[edit on 8-8-2010 by Azp420]




posted on Aug, 8 2010 @ 08:03 PM
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reply to post by Joey Canoli
 



Net force from the bottom part was 1.0W. It never changed.


You ignored when I asked you earlier why you think the bottom only provided a 1.0W upwards force when it should have been capable of providing a lot more. Do you think if we loaded the top section up to become 1.1W (remember, W is the original weight of the top section) that the lower section would still only be able to provide 1.0W of upwards reactional force and therefore collapse?


This shows that you never have even thought of momentum.


I have considered momentum. Because I have a university level understanding of it however, I can see that it in no way affects the derivation I posted.


Again:

P=mv

P is a force vector.


Again, I know how momentum is calculated and momentum is NOT a force. I can also only assume you are referring to it as a vector in an attempt to sound intelligent because you have so far only presented momentum to us in scalar form.


F=ma is not the only way to express the forces involved.

Forces can be applied to the mass from many different sources resulting in a net force in a particular direction which results in an acceleration in the same direction. F=ma is the only way to relate forces to accelerations. You can express the forces any way you like, just come back and relate them to acceleration using Newton's second law of motion.


In order to believe in Chandler's work, then you must also be of the opinion that you can balance a 8 lb brick on your head, or drop it from 20 ft and there will be no difference.


This is not true. I believe Chandler's work to be correct from what I have seen of it but do not hold the opinion you have just stated. You must not understand Chandler's work if you believe that to be a valid comparison. By the way the brick falling from 20 ft would provide a force on the persons head equal to F=ma, = 8 lb times however much the brick decelerated as a result of contact with the persons head (negative acceleration). The stationary brick would only provide a force to the persons head equal to the weight of the brick.


You're delusional if you continue down that road.


It would be delusional of me to design structures based on what was taught in my degree? I think I'll continue down this road, thanks for your concern though.







[edit on 8-8-2010 by Azp420]



posted on Aug, 8 2010 @ 08:37 PM
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Originally posted by iamcpc


I don't know what all you're making up. You refuse to cite your source. You made up that the twin towers collapsed through the path of the most resistance. The truth is, that the twin towers collapsed downward, through their support structure and that the path of the least resistance was through the support structure.



Oh was that a good one,yeh, thats why the rivers go uphill, oh wait...nvm
I just have to laugh at those OSers...

[edit on 8-8-2010 by Juanxlink]



posted on Aug, 8 2010 @ 09:24 PM
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reply to post by weedwhacker
 



Nope...I think you (and many others who continue with this fallacious reasoning) are missing the point...too bad, for it would be nice to have someone finally 'get it', but I suppose some are just too far gone....


I'm still waiting for you to attempt prove my derivation (so called fallacious reasoning) wrong rather than just providing all this big talk. We both know that you can't hold your own getting into the nitty gritty with equations, concepts, derivations and proofs so you fluff up your posts with a lot of big words that are designed to impress people and make it appear as though you are knowledgeable in this field.


Out of ALL the dissecting you did of my thoughts/opinions/descriptions, in the above two posts...I picked this as most demonstrative of the fallacious reasoning.


Don't you really mean out of all the points I made, this is the only one that you can even attempt to argue against (ie find some sort of analogy) and that you're in way over your head arguing the other points? So you disagree with what I have said about structural connections, one of the points that debunks almost your entire post? Why not prove me wrong on that major point? It should be easy if my reasoning is as fallacious as you keep trying to tell everyone it is. Instead you dedicate half your post to a light-hearted joke I slipped in there about superman correcting the sideways toppling top section.

If my point was based on such fallacious reasoning then it should have been very easy for you to prove wrong. You seem to love analogies but don't seem to understand the physics or equations governing them.


Once again, it demonstrates the FALSE impression people are having, regarding the structures' density, composition, and force vectors that were applied, by the INDIVIDUAL components, in a multitude of ways....not infinite, but a very, very large number.


So you're telling me that my degree is based on nothing more than false impressions, as opposed to your obviously very thorough understanding of the entire field of structural engineering?


AS TO the "should have decelerated"? This is seriously flawed reasoning, when you consider the sheer MASS involved!!


I'm aware of the mass involved, if you understood my derivation you would know it is taken into account. Mass is not a force by the way.


YOU, sir or madam, have a very good grounding in the basics --- surely you can grasp the concept of the huge mass, and its momentum, and the resulting forces??


I would hope they don't hand out a BE to anybody who can't grasp those concepts!


Think of common-day analogies, if it will help: Battering rams, wrecking balls, etc.

Those are examples of a SIDEWAYS force of inertia and momentum, and thee impetus of the forces is NOT from gravity alone, but the concept is the same.


Gravity provides most of the force which accelerates a wrecking ball, the people or whatever is swinging the battering ram provides the force which accelerates the battering ram. Why the emphasis on SIDEWAYS?


A two-ton ball of steel, comprising a "wrecking ball" WILL, of course, due to conservation of energy, and such, decelerate slightly upon impacting a target...say a brick wall. BUT, it is miniscule in measurement.


This in no way disproves my statement. Obviously the deceleration is only slight in this scenario due to the huge differences in mass between the ball and the wall. Why don't we look at a scenario where a battering ram must decelerate to the point where it almost completely stops after impact in-order to provide enough force to the object being struck?



F=ma, m is the mass of the battering ram, if F is the force being applied to the door then a is the deceleration of the battering ram. [continued next post]




[edit on 8-8-2010 by Azp420]



posted on Aug, 8 2010 @ 09:25 PM
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reply to post by weedwhacker
 


[continued from previous post]

The battering ram must decelerate so much to provide the required force to open the door that it barely makes it inside the doorway.


It really is a case of the 800-pound gorilla versus the antigue French provincial chair...(just made that up...thought it would evoke a cute mental image).


Are you really trying to compare the top section of the towers crushing the lower section to a wrecking ball destroying a brick wall or an 800 pound gorilla falling on an antique french chair? The lower section was stronger than the upper section for starters...


In essence: We have videos available, plenty of them, that portray the style of building demolition that involves no explosives of any sort --- merely removing a portion of the supporting structure, even on the PERIMETER, and even on only ONE SIDE....and, gravity does the rest, as the mass above begans to fall, CRUSHING, component by component, in a progressive fashion, the rest below it.


Joey posted them in this thread and I discussed them in detail. Turned out they actually helped prove my point rather than his. They're just a few pages back if you want to have a look.


The upper portions in THOSE examples don't "decelerate"


Yes they do, once the top section is past the initiation zone and in contact with the stronger lower section. It is the ONLY way the top section can provide a force on the lower section. You may not break Newton's second law of motion, F=ma. See my previous comments about them.


BTW, accumulates MORE mass with each passing microsecond.


The accumulation of more mass should be balanced by the inertia required to accelerate the extra mass to the same velocity as the main mass.

Your irrelevant analogies are proving nothing. Give us some physics or concede that you don't have the knowledge or understanding to do so and hence your belief in the OS from a physics point of view is based on a reliance of other people telling you how it should be or trying to compare the towers to extreme analogies.

Peace out.
420



posted on Aug, 9 2010 @ 08:59 AM
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Originally posted by Azp420



In order to believe in Chandler's work, then you must also be of the opinion that you can balance a 8 lb brick on your head, or drop it from 20 ft and there will be no difference.


This is not true. I believe Chandler's work to be correct from what I have seen of it but do not hold the opinion you have just stated. You must not understand Chandler's work if you believe that to be a valid comparison. By the way the brick falling from 20 ft would provide a force on the persons head equal to F=ma, = 8 lb times however much the brick decelerated as a result of contact with the persons head (negative acceleration).


I find it fascinating that you will admit here that the falling brick will result in an overload on your head, and yet totally miss the point that the falling upper block will overload the lower part in the same way due to momentum.

As I've said, there is zero need to preweaken the lower part when momentum of the upper part is taken into consideration.

Explain how in your hypothetical question, why it is necessary to clear away the lower structure with explosives to get an overload of .7W, when momentum will result in an overload.



posted on Aug, 9 2010 @ 04:13 PM
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Originally posted by Joey Canoli
I find it fascinating that you will admit here that the falling brick will result in an overload on your head, and yet totally miss the point that the falling upper block will overload the lower part in the same way due to momentum.


I find it fascinating you fail to understand that the brick would not keep going and crushing your body to the ground symmetrically whilst not losing any momentum from resistance and friction.


As I've said, there is zero need to preweaken the lower part when momentum of the upper part is taken into consideration.


This is all hypothetical because no block of floors dropped in either of the towers. But having said that...

What you are saying is impossible if resistance and Newtons laws of motion are taken into consideration. Oh and throw angular momentum in there if WTC 2 is taken into consideration.

Why is it you fail to see the complete picture every time Joey? Why is it you always always always fail to consider resistance? Is it because when you consider resistance it contradicts your arguments?

No dropping floors...



posted on Aug, 9 2010 @ 07:49 PM
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reply to post by Joey Canoli
 


Joey, anybody sitting on the fence in regards to 9/11 can see that you are unable to provide a decent rebuttal to any of the points that I'm making. It's painstakingly obvious to those who can grasp the physics and are intelligent enough to not allow their belief systems or other motives to cloud their judgment.


I find it fascinating that you will admit here that the falling brick will result in an overload on your head, and yet totally miss the point that the falling upper block will overload the lower part in the same way due to momentum.


Here we go again. You are unable to provide a logical argument against any of my points to you just attempt to misrepresent what my point is. I'm not sure why you have this religious belief in what your government tells you. I never said the falling top section wouldn't overload some of the undamaged bottom section. All I said was that the only way the top section could have accelerated in the manor it did was if the bottom section provided less of a reactionary force on the top section than when it was supporting it stationary. It then provided logical mathematical proof of this. It then leaves the obvious question as to why that is the case. Even if it was nothing sinister engineers would damn well want to make sure a structure couldn't accelerate through itself again. Covering up the truth is not looking after the interests of the honest citizen. Why do you OS believers insist on coming up with these irrelevant analogies? Is an 8 lb brick dropped on a persons head from 20 ft really a logical comparison to the top third or less of a twin tower dropped through ~6 floors onto the bottom section of the tower? Does it disprove the point I was making? I already showed how the brick would decelerate but you decided to ignore that and keep running with it anyway. Why can you not provide derived proof of how you say the structure is able to accelerate through itself?


As I've said, there is zero need to preweaken the lower part when momentum of the upper part is taken into consideration.


So you can't refute any of my post disproving your claims about momentum acting as an accelerating force on the upper section but you continue to hold on to this faith that momentum is the key that proves what you believe to be true? Fascinating.


Explain how in your hypothetical question, why it is necessary to clear away the lower structure with explosives to get an overload of .7W, when momentum will result in an overload.


Go back and try to read my post without letting your belief system filter the information. Momentum IS NOT in any shape or form an accelerating force. The only downwards force which can accelerate the top section downwards is gravity. No top section can accelerate uniformly and constantly through any properly and typically designed, undamaged lower section because the imbalance of forces will always be in favor of the lower section, as I proved.









[edit on 9-8-2010 by Azp420]



posted on Aug, 12 2010 @ 12:31 AM
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Originally posted by Azp420

I never said the falling top section wouldn't overload some of the undamaged bottom section.


Then you have lost the plot entirely.

If you recognize that the falling upper part can overload the lower, but still insist that the only way for the collapse wave to accel at .7g is with explosives, then you don't have a handle on the problem.



posted on Aug, 12 2010 @ 01:03 AM
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Why are we even talking about the physics of 911?

Isn't it obvious that Bush was "conveniently" reading stories to grade school students when this happened? It made him look like the perfect father figure.

Strange how the media found him, "so conveniently" in that classroom as his agents came to tell him of what happened.

He seemed so calm, didn't he? As if he was prepared for the news.

Sorry, but I knew from the beginning that it was planned.



posted on Aug, 12 2010 @ 01:18 AM
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OK. Now that I've thought about it, I need to put it another way.

911 was the perfect way to bring about "Homeland Security" or in other words, domination of the people's liberties. A police state. Whatever you want to call it.

It was planned for a long time so that other forces could be set in place. What is disturbing is that I think this was only a precursor of what is yet to come.

Good site. Let us educate one another.



posted on Aug, 12 2010 @ 05:01 AM
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Originally posted by Joey Canoli

Originally posted by Azp420

I never said the falling top section wouldn't overload some of the undamaged bottom section.


Then you have lost the plot entirely.

If you recognize that the falling upper part can overload the lower, but still insist that the only way for the collapse wave to accel at .7g is with explosives, then you don't have a handle on the problem.



So here is your logic/understanding of physics:
"If the upper section can overload the lower then it should be able to accelerate through it at whatever rate it wants."

You continue to miss the point time and time again. Of course if the top section legitimately accelerated at near free fall through the legitimately damaged ~6 stories of initiation zone then impacted the undamaged lower structure it would do some damage to the lower structure, overloading some of the members or connections. This is not a suspicious way for a structure to behave. In a non-suspicious scenario the top section would be decelerated as it overloaded some of the members and connections, if it had enough mass and velocity (momentum) to overload.

A suspicious way for a structure to behave, as I have proven in this thread, is for it to accelerate through undamaged portions of itself uniformly and constantly. You have tried and failed to find errors in my proof. I also never said that my proof pointed to explosives.

Do you see it now?

I'm not sure what kind of personal logic you used to come to the conclusion that I had "lost the plot entirely" for making a distinction between what aspects of the collapse were suspicious and what were not. Perhaps it is you who doesn't have a handle on the problem? You have already lost any credibility you once had on ATS in regards to arguing 9/11 from a physics or logical point of view. You are beginning to turn into a comedy act.




[edit on 12-8-2010 by Azp420]



posted on Aug, 12 2010 @ 05:16 AM
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reply to post by zsuzsology
 



Why are we even talking about the physics of 911?


Maybe it is just because I think from an engineering perspective, but for me the physics of 9/11 are what proved it. There were many, many suspicious actions and events but most could have been a coincidence, however unlikely (like both 9/11 and 7/7 having training exercises based around similar scenarios on the same day). The physics is pretty clear cut, indisputable evidence however. Most things can be explained away with a clever story, the physics cannot.



posted on Aug, 12 2010 @ 11:07 AM
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reply to post by Azp420
 


Here....all most anyone ever does is talk and not understand what the other is saying, about the physics.

The power of the computer, and the ability to model REAL three-dimensional physics, is undisputed, would you not agree??

SO...instead of trying to school those who either fail, or refuse, to understand the dynamics involved, and the PHYSICS of all the various components that made up the structure of the WTC Towers, here is a video --- since people loves them videos better, and makes it easier to explain and visualize:



I suggest a review of others that are related to that one. Both on YT, and perhaps also on other video-sharing sources. (However, there are a host of really BAD videos that will pop up too...crap that are usually laughable, and they are, unfortunately, all jumbled and linked together).



[edit on 12 August 2010 by weedwhacker]



posted on Aug, 12 2010 @ 07:04 PM
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reply to post by weedwhacker
 



Here....all most anyone ever does is talk and not understand what the other is saying, about the physics.


It is the Physics of 9/11 thread after all. I understand all the physics being discussed in this thread, it really is being kept to a pretty basic level. If it is not the physics of 9/11 that your belief in the OS is based on then may I ask what it is based on? Are there no debunkers on ATS who know physics?


The power of the computer, and the ability to model REAL three-dimensional physics, is undisputed, would you not agree??


The "power" is fairly undisputed, but a model is still only as good as the quality of the input parameters and interpretation of the results. Just about any desired result can be "modeled" (fantastic fear mongering results from global warming computer modeling is an example).


SO...instead of trying to school those who either fail, or refuse, to understand the dynamics involved, and the PHYSICS of all the various components that made up the structure of the WTC Towers, here is a video --- since people loves them videos better, and makes it easier to explain and visualize:


Sorry, what are you trying to prove? This video is just an animation coupled with a finite element model of a plane impacting a tower and showing the damage it caused in the initiation zone. We already know planes were flown into the twin towers. I don't think there are many who would disagree that a plane impact would do a lot of damage to a building either.

This seems to be another "zomg look at all the damage, the OS must be true!" and a distraction away from the huge red flag (the top section shouldn't have been able to accelerate through the rest of the tower). It is NOT complicated physics. I used concepts and equations that are taught to high school students being taught mechanics (at least at my high school). If you can't disprove it then what is stopping you from accepting it as truth?

I realise the ramifications of planes and fires not bringing down the building are too much for some. It is hard for some people to not have faith in any government. To realise that they need to look after themselves and their own best interests because they can't trust the government to. That they need to think and act for themselves and not just how the government tells them to.






[edit on 12-8-2010 by Azp420]



posted on Aug, 14 2010 @ 01:03 AM
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Originally posted by Azp420

So here is your logic/understanding of physics:
"If the upper section can overload the lower then it should be able to accelerate through it at whatever rate it wants."


Nope.

the accel rate would depend on the structure and overload.


In a non-suspicious scenario the top section would be decelerated


How much would depend on the structure and overload.

You are saying that it should slow down. You reject the notion that it can accel at 70% of ffa. How can you make the correct determination?

You don't have the answer to this cuz you don't have the structural docs, nor have you done an analysis.


A suspicious way for a structure to behave, as I have proven in this thread, is for it to accelerate through undamaged portions of itself uniformly and constantly.


How much would depend on the structure and overload.

[uote]You have tried and failed to find errors in my proof.

Sure I did.

You said:

Downwards forces acting on the top section:
Gravitational, with a magnitude of 1.0W (W was defined earlier)

Upwards forces acting on the top section:
Upwards resistance force provided by lower structure, magnitude unknown at this point.

But there is also a downwards load imposed on the lower part that you have ignored.

Momentum of the top section.

My 6 year old understands momentum and its effects. He understands that when I place the 7lb bag of catfood into his arms, that he can help carry the groceries in. But he also innately understands that if I drop it into his arms, he will not be able to keep it from falling onto the garage floor.

According to you, the fact that he could only decel the bag a little is proof that his arms somehow got weaker.

That is insane.



posted on Aug, 14 2010 @ 08:41 PM
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reply to post by Joey Canoli
 


You are saying that it should slow down. You reject the notion that it can accel at 70% of ffa. How can you make the correct determination?

You don't have the answer to this cuz you don't have the structural docs, nor have you done an analysis.


I've already provided a thorough derivation of why it should not have been able to accelerate at 70% FFA. You are yet to find any errors in it or prove it wrong. I cannot give a figure on what the rate of deceleration should have been.


But there is also a downwards load imposed on the lower part that you have ignored.

Momentum of the top section.


Momentum is not a force or a load. I've told you this before but don't take my word for it, ask someone with a credible understanding of physics. There is no way in this universe that momentum can act as a downwards accelerating force on the top section. That's not what momentum is lol.


My 6 year old understands momentum and its effects.


Maybe you shouldn't rely on him to teach you about momentum. It was wrong of him to tell you momentum is a force. I also understand momentum and it affects. My understanding is based on what professors taught me during my Bachelors of Engineering.


He understands that when I place the 7lb bag of catfood into his arms, that he can help carry the groceries in. But he also innately understands that if I drop it into his arms, he will not be able to keep it from falling onto the garage floor.


Nice analogy. How is does this differ to where I discussed in my last post that if the top section was dropped through ~6 stories that I wouldn't be surprised if some of the lower structure was overloaded. You continue to miss the point. Maybe the physics are getting too complicated for you to understand at this point? I'll try to help you get it bellow.


According to you, the fact that he could only decel the bag a little is proof that his arms somehow got weaker.

That is insane.


You're right, that is insane. Good thing I've never said or implied that. You still don't even understand my point. How many times does it take for you to read something and comprehend it? I'll make it as clear for you as I can:

The fact that he could decelerate the bag a little is proof that his arms DID NOT get weaker.

Are you with me so far? If the lower section of a twin tower (which represent the child's arms in your analogy) was able to decelerate the top section (which represents the bag) "a little" then this would also be proof that the lower section DID NOT get weaker.

Do you know the difference between what has just been described and actually happened? The lower section DID NOT decelerate the top section. THIS is what is highly suspicious about the manor of collapse. The top section accelerated constantly and uniformly through the bottom section. Let's relate this back to your analogy and discuss the governing equations.

Let W = the downwards force due to gravity acting on the mass of the bag (its weight).

You described how when the bag was static, the child is able to hold the bag. His arms must be providing an upwards resistance force on the bag equal to the downwards gravitational force acting on the bag. The net force on the bag is therefore zero. F=ma, since F=0 and m=7lb a must = 0 (no acceleration in any direction, a=F/m).

Now the bag is dropped from some height. The bag gains momentum equal to it's velocity times 7lb. This momentum is not a downwards force accelerating the bag. Gravity is the only downwards force accelerating the bag. There are multiple methods to describe what happens next (such as conservation of energy, conservation of momentum and free body force-accelerations). As you seem to be confusing and wanting to mix the conservation of momentum method [continued next post]



[edit on 14-8-2010 by Azp420]



posted on Aug, 14 2010 @ 08:42 PM
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reply to post by Joey Canoli
 


[from previous post] with the free body method so I will cover both. First, conservation of momentum:

As stated previously, the momentum of the bag right before the point of impact is equal to its velocity times 7lb because p=mv. The child's arms also have momentum equal to p=mv, initially this obviously =0. If the child is rigidly holding his arms some of the bags momentum would be absorbed because an external force is decreasing momentum (p decreases and therefore v must decrease). If the child holds his arms limp as the bag impacts then no external force is present and conservation of momentum is applied. This means total p remains constant before and after the collision. As the bag impacts the arms some of the momentum from the bag is transferred into the arms as the bag knocks the arms out of the way. The arms now have some momentum equal to the mass of the arms times the average velocity (immediately after impact) of the moving arms. As total momentum is conserved, this means the momentum of the bag had to decrease (by an equal amount to the increase in the momentum of the arms). As p=mv, the mass of the bag remained constant so the velocity of the bag had to decrease (over a period equal to the duration of the impact). As we all know, a decrease in velocity is another way of saying deceleration.

The free body force-acceleration method I have gone over many times on this thread because it is the simplest method. The bag is dropped and the downwards force of W accelerates the bag downwards. The bag impacts the child's arms and the forces acting on the bag are examined at this point in time. W remains as the only downwards force acting on the bag. The child's arms provide some upwards reactional force on the bag. We do not know what this is, BUT we do know that when the child was holding the bag stationary it was able to provide at least 1.0 times W upwards force on the bag to cancel the downwards force of W acting on the bag. It is therefor safe to assume that the child is still capable of providing 1.0W OR GREATER upwards reactional force. And quite rightly in your example he does, and the bag is decelerated due to the upwards force acting on the bag being greater than the downwards force acting on the bag. F=ma, F is positive in the upwards direction therefore a is also positive in the upwards direction (upwards acceleration or downwards deceleration).

The only way for the child's arms to not decelerate the bag is if the child's arms provided a SMALLER upwards force on the bag than when he was just holding it still (like if the bag dropped and he tried to move his arms downwards out of the way).

If you still can't comprehend what I am saying then I ask you this:

You claim momentum provides 0.7W (where W is the weight of the top section) of force downwards (despite momentum not being a force).
You also state momentum, p=mv.
My question is, how on earth do you obtain 0.7W by multiplying the mass of the top section times the velocity of the top section, especially as the velocity of the top section is constantly changing throughout the collapse due to it undergoing constant acceleration?

You don't even understand the physics of what you are claiming, yet you continue to believe it is correct purely on faith (in the government). Your beliefs regarding 9/11 are not based on logic, they are based on faith. Are you religious by any chance Joey?





[edit on 14-8-2010 by Azp420]






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