So who the heck ever said "Pull it" was slang for controlled demolitions?

Originally posted by Fluffaluffagous
For the record, I must say that this is rather a display of ignorance than not understanding physics.

Ummmmm... he says that PE pushes UP??? ANd that there is no PE in relation to the the ground (where the collapses ended)????

Wow....

I'd say that ignorance and not understanding physics, coupled with very healthy doses of arrogance and Dunning-Krueger....

You're just agreeing with someones else's ignorant misunderstandings of physics, to the point that he failed to even comprehend what was being said. I was trying another way to explain the physics of colliding objects. And he claimed to be an electrical engineer, until I proved he wasn't by asking simple questions he refused to answer.

What he said about PE was taken out of context. I was just trying to get him to understand equal opposite reaction, and the fact that regardless of PE and momentum, the forces on two colliding floors would be equal, thus both floors would be crushed, thus the falling floors would not be able to stay solid while crushing all the lower floors, the forces would be reduced as the resistance builds, and the collapse would have stopped. Forces always come in equal and opposite pairs. PLB wanted to claim that the PE of the falling floors would be enough to squash the static floors, while ignoring the laws of motion this is all based on. PE becomes KE as soon as it starts to move. The static floors have PE, because they have the potential to resist the force of the falling floors.

This is basic physics 101, not rocket science.

reply to post by ANOK

the forces would be reduced as the resistance builds

No the force would build as the falling mass increases.

Originally posted by ANOK

Originally posted by Fluffaluffagous
For the record, I must say that this is rather a display of ignorance than not understanding physics.

Ummmmm... he says that PE pushes UP???

The static floors have PE, because they have the potential to resist the force of the falling floors.

--we've gone over this more than once already. For the sake of argument I'd like to assume for the moment that your understanding of physics and potential energy is correct. Assuming all that, could you answer one question?

If, as you say, the potential energy of an object depends upon empty space below it, or between it and the earth, how can you say that the static floors have potential energy? After all, they have no empty space beneath them, right?

Originally posted by samkent
reply to post by ANOK

 

the forces would be reduced as the resistance builds

No the force would build as the falling mass increases.

Hi sam ,
long time no see.
By the way can you shoot me the formula or math for your assertion here???
Also where is anything falling???
There is always continuous structure below.
Well of course there wouldn't be if it was BLOWN OUT.
now would there be.
ljb

Originally posted by ANOK
LOL I have explained this many times.

When steel heats up it expands, do you agree?

When steel expands it gets bigger, do you agree?

When it expands that expansion has to go somewhere, do you agree?

That expansion causes the sagging, do you agree?

That sagging is a result of the steels expansion, do you agree?

If the steel sags due to it's expansion, it's because it has nowhere else to go, do you agree?

So if it sags, because it has nowhere else to go, then where is the pulling force coming from? How are the trusses putting any more force on the columns than it already did.

Indeed LOL. How many times did we get over this and you still don't get it


What you still don't understand, is that after all what you just wrote has happened, and the steel heats up even more, it becomes too weak to carry the load it bears. It starts acting like a chain (catenary action). I have pointed you to Wikipedia pages and to papers that confirm this with experimental data. You just keep denying. I predict that you will ignore this post too, because you are too busy with your oh so interesting real life .

And the question you all ignore, why didn't the 5/8", and 1", bolts fail before the obvioulsy more massive columns did?

You mean to say, you ignore my answers because your are too busy with your oh so interesting real life. I already explained that. I will do so briefly again, as I predict you will just ignore this post as usual.

First of all, I don't need to explain that to you. Its not my theory. Its NIST's theory, and I am completely open to alternative theories.

Secondly, you completely misunderstand what is happening. The pulling trusses don't make the columns fail. The load they are bearing made them fail. The only thing the trusses did (according to NIST that is), is initiate the buckling by deforming the columns.

If your claim is that a weaker object can not deform a stronger object, then you again demonstrate that you don't now jack about physics. According to that silly notion, a crane can never bent a column, as the axle inside the hook is thiner than the column.

Your part about PE pushing up is just a misunderstanding of what I was trying to explain. What I meant was that there is PE in the lower floors as well as the upper floors. It was in response to your stupid claim that momentum, and PE, was all that mattered, and you ignore the laws of equal opposite reaction and momentum conservation.

Sure, you realized your massive blunder and tried to weasel yourself out of it. I don't think you even came with this nonsense in a reply to me.

I will ask the question you skillfully avoided last time again. What happens to the momentum of the top section once it start to move after the supporting columns fail? Does it increase, decrease or stay the same? Keep in mind the conservation of momentum.

Looking at picture? That didn't actually happen? What are you talking about? Stop talking in riddles and show YOUR physics that proves I'm wrong.

What I am talking about is that the chapter that you got those images from says in big bold letters that those are the simulation results for the scenario where the debris of the WTC tower did not hit WTC 7. Do you realize that in reality debris of the tower did hit WTC 7? And do you understand that those images you posted do not correspond with what we see on video? (don't answer).

From someone who never even attempts to prove he understands physics that is hilarious. You didn't address one of my points, just another failed attempt to discredit. You guys should be put on report, in fact I'd have fired you by now, and got someone who at least can argue points raised. You are doing more to discredit the OS then you are helping it. But then again who would do your job if they weren't desperate for work? How come Mr.Electrical engineer you're not working in your field, or do you get lots of breaks to post on ATS?

Just another lame, failed, attempt to discredit. You're not very good at this PLB.

In the end, all you have to offer are hollow words. Nothing to show for. When confronted with real physics, you are all in a sudden too busy with your oh so interesting real life. And this post will likely go ignored.

Originally posted by ANOK
What he said about PE was taken out of context. I was just trying to get him to understand equal opposite reaction, and the fact that regardless of PE and momentum, the forces on two colliding floors would be equal, thus both floors would be crushed, thus the falling floors would not be able to stay solid while crushing all the lower floors, the forces would be reduced as the resistance builds, and the collapse would have stopped. Forces always come in equal and opposite pairs. PLB wanted to claim that the PE of the falling floors would be enough to squash the static floors, while ignoring the laws of motion this is all based on. PE becomes KE as soon as it starts to move. The static floors have PE, because they have the potential to resist the force of the falling floors.

This is basic physics 101, not rocket science.

edit on 4/14/2012 by ANOK because: This space for rent, U2U for rates...

Taken out of context? That is literally what you said and it is wrong in any imaginable context. I am not ignoring the laws of motion, you just fail to understand them. You keep ignoring the floors that have already failed that are between the intact floors of the top and lower section. In your fantasy physics they disappear, and with each impact, two intact floor collide.

Man you are just too funny. Just too bad you will run away again.

Originally posted by ANOK

This is basic physics 101, not rocket science.

It sure is.

And by stating that there is PE pushing up, you have proven that you are clueless.

You know just enough to get stuff wrong, while still believing that you are right.

This is the Dunning-Krueger effect.

Originally posted by ANOK

When steel heats up it expands, do you agree?

When steel expands it gets bigger, do you agree?

When it expands that expansion has to go somewhere, do you agree?

NIST agrees with this. They state that the expanding trusses pushed out the ext columns about an inch or two. An independent study done by truthers agrees.

That expansion causes the sagging, do you agree?

That sagging is a result of the steels expansion, do you agree?

If the steel sags due to it's expansion, it's because it has nowhere else to go, do you agree?

No to all.

So if it sags, because it has nowhere else to go

Incorrect premise. the trusses are able to initially push out the ext columns. this happens at 300-400C IIRC, before they sag.

then where is the pulling force coming from? How are the trusses putting any more force on the columns than it already did.

As the trusses further heat up, they begin to sag, and the columns pull back in. FEA and known properties of steel prove this.

And the question you all ignore, why didn't the 5/8", and 1", bolts fail before the obvioulsy more massive columns did?

Cuz the truss pull are not the only reason that the ext columns buckle. Read the NIST report. It shows that the core columns shortened first, from plane impacts and creep. the loads came off the core columns as a result and were redistributed to the ext columns, mainly in the center dozen or so, by the hat truss. the ext columns were also heated by the fires. In summary, several factors are responsible for the pull in.

Incorrectly representing the problem from NIST shows that you are either dishonest or ignorant of what you are arguing against.

Originally posted by samkent

No the force would build as the falling mass increases.

No they wouldn't.

The falling mass would not increase, as the collapse should never have started in the first place.

A falling mass cannot increase against a mass that is larger. The mass of the static floors is not going to be added to the falling floors. As each floors impacts, both the impacting and impacted floors lose mass, as mass is lost so is Ke. Ke is also lost to heat, deformation, sound. For the collapse to accelerate to its foundation would take a constant increase in Ke, which is impossible without an outside force (and no its not gravity before you try that one). As you keep failing to understand, equal opposite reaction and momentum conservation will not allow a smaller mass to destroy a larger mass. 15 falling floors can not destroy 95 floors. Even if for every falling floor two static floors are destroyed, you still have an incomplete collapse. The top floors would be destroyed, ejected outside the footprint, before they could crush lower floors. (and yes the majority of the mass of WTC 1&2 was found in a 360s arc around the towers).



I know you like to think the whole top mass was acting on one floor, but that is not the case. IF the connections of the first impacted floor failed then the connections of the first impacting floor would also fail. The force would be equal on both floors. The mass above the first impacting floor would act on that impacting floor, not the first impacted static floor, because it is floors separated by columns not one solid lump.

So when are you going to address my points about the sagging trusses, because if you can't prove the sagging truss hypothesis, talking about the collapse is irrelevant. When are you going to address the contradiction with connections being strong enough to allow the columns to be pulled in by the trusses, and the lightweight floor assemblies causing the connections to fail? It would take more energy to cause the columns to be pulled in than it would to break the connections.

You can't can you, all you can do is attempt to discredit my claims, and like an expert who only has to disagree but not explain why you disagree. Other than point at the NIST report, or other official excuses.

(I'm not replying to all the posts directed at me, sorry but you need to stop making mass replies to one post, have you all not get better things to do? Go ahead accuse me of ignoring your questions, I think I have said all I need to)

Originally posted by ANOK

The falling mass would not increase, as the collapse should never have started in the first place.

Well there's a circular argument if there ever was one....

As each floors impacts, both the impacting and impacted floors lose mass

Prove with math that enough mass is lost to prevent increase in KE. You are implicitly admitting that IF mass increases, then KE might increase.

Now prove it.

Ke is also lost to heat, deformation, sound.

How much? Prove it with math.

For the collapse to accelerate to its foundation would take a constant increase in Ke

FYI, it didn't accelerate all the way to the ground. Troofers have done measurements that show a fairly steadt state velocity near the end.

But your premise is correct.

which is impossible without an outside force

You presume that you are correct that enough mass is lost during the collisions (ejections?)

You haven't proven this yet. Merely stated that you are right.

As you keep failing to understand, equal opposite reaction and momentum conservation will not allow a smaller mass to destroy a larger mass.

The mass above the first impacting floor would act on that impacting floor, not the first impacted static floor, because it is floors separated by columns not one solid lump.

This destroys your whole "15 floors cannot destroy 95 floors" trolling point. Let's see if you can figure out why.....

Originally posted by ANOK

Originally posted by Fluffaluffagous
For the record, I must say that this is rather a display of ignorance than not understanding physics.

Ummmmm... he says that PE pushes UP??? ANd that there is no PE in relation to the the ground (where the collapses ended)????

Wow....

I'd say that ignorance and not understanding physics, coupled with very healthy doses of arrogance and Dunning-Krueger....

You're just agreeing with someones else's ignorant misunderstandings of physics, to the point that he failed to even comprehend what was being said. I was trying another way to explain the physics of colliding objects. And he claimed to be an electrical engineer, until I proved he wasn't by asking simple questions he refused to answer.

What he said about PE was taken out of context. I was just trying to get him to understand equal opposite reaction, and the fact that regardless of PE and momentum, the forces on two colliding floors would be equal, thus both floors would be crushed, thus the falling floors would not be able to stay solid while crushing all the lower floors, the forces would be reduced as the resistance builds, and the collapse would have stopped. Forces always come in equal and opposite pairs. PLB wanted to claim that the PE of the falling floors would be enough to squash the static floors, while ignoring the laws of motion this is all based on. PE becomes KE as soon as it starts to move. The static floors have PE, because they have the potential to resist the force of the falling floors.

This is basic physics 101, not rocket science.

edit on 4/14/2012 by ANOK because: This space for rent, U2U for rates...

Anok, you are not even close.

Google the law of conservation of momentum and learn what impulse/momentum change means.

Specific material and engineering dynamics aside, this is first day of school stuff. In an undamaged structure the action-at-a-distance force of gravity pulling down and the contact normal force pushing back are equal and balance at equilibrium.

In this example the compromised structural integrity is manifested as a reduction in the normal force opposing gravity resulting in an unbalanced force and the building starts to move, in this case down pushed by the now unequally greater force of gravity.

This would be the collapse initiation.

When the building starts moving you now have momentum which is a sum of mass, velocity and direction. The mass accelerates pushed by the momentum increases. Gravity and momentum are combined on the same vector as the upper mass pushed by the now unbalanced force impacts the still balanced force of the lower mass in quantity of force and time called an impulse. The impulse creates an unbalanced force acting on the lower mass which begins to move along the same vector as the upper mass due to conservation of momentum.

This would be called collapse progression.

Separately, -PLB- is absolutely correct in his correction of your nonsensical and flat wrong attempt to explain the mechanism driving the truss sag as thermal expansion.

I would add that generous connection tolerances are provided to allow for a considerable amount of movement however if somebody poked the pooch and did install any of the floor components in such a way as to hinder their movement allow some part of the system to bind, the steel truss chords and webbing would first twist then bow laterally a long time before they crowned or deflected vertically.

Anok, are you familiar with the Dunning-Krueger effect as referenced above by ATS poster Fluffaluffagous?

Allow me to provide some particulars...

The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than average. This bias is attributed to a metacognitive inability of the unskilled to recognize their mistakes...

...Dunning and Kruger were awarded the 2000 Ig Nobel Prize in Psychology for their report, "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments".

Dunning–Kruger effect

Sound like anyone you might know?

reply to post by Drunkenparrot


Here is where you go ignorant.
In FRAME only a small portion of the structure suffered temporary SPACE
Most of the structure remained static there for would not have contributed to momentum in any way. Have a look....


Momentum
From Wikipedia, the free encyclopedia


If an object is moving in any reference frame, then it has momentum in that frame. It is important to note that momentum is frame dependent. That is, the same object may have a certain momentum in one frame of reference, but a different amount in another frame. For example, a moving object has momentum in a reference frame fixed to a spot on the ground, while at the same time having 0 momentum in a reference frame attached to the object's center of mass.

The amount of momentum that an object has depends on two physical quantities: the mass and the velocity of the moving object in the frame of reference. In physics, the usual symbol for momentum is a boldface p (bold because it is a vector); so this can be written


where p is the momentum, m is the mass and v is the velocity.

According to Newton's second law, the rate of change of the momentum of a particle is proportional to the resultant force acting on the particle and is in the direction of that force. The derivation of force from momentum is given below.
E F= ma translated seperate parts of the frame equal mass accelorated.


This formula changes drastically with BOMBS C4 and other explosives.
your welcome ljb

Originally posted by longjohnbritches
Here is where you go ignorant.
In FRAME only a small portion of the structure suffered temporary SPACE
Most of the structure remained static there for would not have contributed to momentum in any way. Have a look....

I am going ignorant also. What on earth are you saying here?

The predominant reason that I believe 9/11 was a complete lie is because, as I watched it live, it was obviously a staged incident. Anyone with a shred of engineering knowledge/common sense could see those buildings were demolished.

Originally posted by Meatballglove
The predominant reason that I believe 9/11 was a complete lie is because, as I watched it live, it was obviously a staged incident. Anyone with a shred of engineering knowledge/common sense could see those buildings were demolished.

What a pity all those dumb civil engineers around the world are too stupid to see things with your clear vision.

reply to post by Alfie1


Its a well known fact that, unlike truthers, most engineers lack any engineering knowledge/common sense. The fact that they, unlike truthers, build and design the most amazing stuff, is just coincidence.

reply to post by longjohnbritches


I cant help but point out the irony of you using the word ignorant in this conversation and posting the nonsense you did.

Another truther that has not spent a day in a physics class telling everyone how it is.

Would you be so kind to demonstrate your obviously recent epiphany of brilliance mathematically?

Erm, yeah all good except I'm an engineer. The term truther suggests some sort of organisation. What is wrong with just being intelligent enough to see an obvious deception, your label not mine.

Originally posted by Meatballglove
Erm, yeah all good except I'm an engineer. The term truther suggests some sort of organisation. What is wrong with just being intelligent enough to see an obvious deception, your label not mine.

edit on 15-4-2012 by Meatballglove because: needed second line

I don't believe you. If you were you couldn't have made such a jaw-droppingly naive comment.

I don't understand why that is naive. Why must everyone with a free mind be labeled a truther. Does that make everyone else a liar? No. Don't be so patronising.