Physics of 9/11...

Originally posted by richierich
Such silly arguments..freefall WAS documented in Bldg. 7. NIST admitted it.

And to anyone that spends the time reading the report, with the intent of understanding it FIRST, there's a rather banal and simple explanation for it.

Unbraced, long span columns.

Engineering proves it.

However, truthers ignore it.

reply to post by Joey Canoli


source for the unbraced columns? I have never heard that the columns were unbraced.

Originally posted by dudly
I have never heard that the columns were unbraced.

I know you haven't.

Cuz it's in the NIST report.

They describe the horizontal, internal collapse of the floors over several floors. The floors brace the columns.

And then engineering explains how long unbraced columns are not only more prone to buckle, but when they do, give very little resistance to the weight that they formerly held up.

reply to post by Joey Canoli


So now that freefall is admitted by NIST, it is all explained away by the totally unproven assumption that the entire span, all the way across the bldg would give way at the same time, right? Unreal. just astounding.

Freefall CANNOT be explained by any nonsense you assume. SHOW us the NIST report that says that all of the connections and all of the beams simply gave way all at once...it does not exist.

The desperation of the official story cultists is becoming obvious.

If all you can do is claim that the entire building was constructed so poorly and so weakly that it could give way TOTALLY and SIMULTANEOUSLY across the entire span, then you have lost and should retreat. To imagine that a building as robust as 7 could, all at once, fail at the bottom PERFECTLY and mimic a demolition is to stretch the imagination to the breaking point and far beyond.

What was the inititing factor? What caused the entire lower parts to simply LOSE ALL RESISTANCE at the exact same time? Tell us please.

Tell us how it happened, because the government cannot. If you know then share it please. I want to know HOW the ENTIRE span could lose all resistance at the same time.

Your answers never satisfy, never explain, never have proof...all you can do is pick the weakest and least likley scenario because there really is NO OTHER way to try and prop up the official lie.

Fires above cannot cause the total and simultaneous failure of all major beams below...cannot happen..did not happen.

How anyone can defend the official story with a straight face is beyond me.

Originally posted by richierich
reply to post by Joey Canoli

 

So now that freefall is admitted by NIST, it is all explained away by the totally unproven assumption that the entire span, all the way across the bldg would give way at the same time, right? Unreal. just astounding.

Freefall CANNOT be explained by any nonsense you assume. SHOW us the NIST report that says that all of the connections and all of the beams simply gave way all at once...it does not exist.

The desperation of the official story cultists is becoming obvious.

If all you can do is claim that the entire building was constructed so poorly and so weakly that it could give way TOTALLY and SIMULTANEOUSLY across the entire span, then you have lost and should retreat. To imagine that a building as robust as 7 could, all at once, fail at the bottom PERFECTLY and mimic a demolition is to stretch the imagination to the breaking point and far beyond.

What was the inititing factor? What caused the entire lower parts to simply LOSE ALL RESISTANCE at the exact same time? Tell us please.

Tell us how it happened, because the government cannot. If you know then share it please. I want to know HOW the ENTIRE span could lose all resistance at the same time.

Your answers never satisfy, never explain, never have proof...all you can do is pick the weakest and least likley scenario because there really is NO OTHER way to try and prop up the official lie.

Fires above cannot cause the total and simultaneous failure of all major beams below...cannot happen..did not happen.

How anyone can defend the official story with a straight face is beyond me.

It's a lot easier to defend the OS about the collapse of the twin towers. WTC tower 7 was different because you could not clearly see the damage done to the building and it was not hit by 110-150 ton 500 mile per hour airplanes.

Originally posted by richierich

So now that freefall is admitted by NIST, it is all explained away by the totally unproven assumption that the entire span, all the way across the bldg would give way at the same time, right?

That is the nature of steel framed structures and load transfer. Engineering explains it. Your incredulity does not justify your belief.

SHOW us the NIST report that says that all of the connections and all of the beams simply gave way all at once

Strawman.

Why would it be necessary to have ALL the connections give way all at once? Justify your position by giving a detailed engineering papaer that backs this statement, or it is proof that you're making stuff up.

If all you can do is claim that the entire building was constructed so poorly and so weakly

Strawman.

that it could give way TOTALLY and SIMULTANEOUSLY across the entire span,

Another strawman. the building collapse started when the interior columns collapsed. It then took about 6.5 seconds for the load transfers to become more than the remaining columns could hold up over their long, unbraced lengths.

If you have something other than your incredulity, please feel free to present it.

and mimic a demolition

It mimiced a gravity collapse, which it was.

What was the inititing factor? What caused the entire lower parts to simply LOSE ALL RESISTANCE at the exact same time? Tell us please.

The interior collapses reduced the load carying capacity of the remaining columns by unbracing them over long lengths.

When a column buckles, there is a condition called dynamic snap through that explains the rest. It is in many engineering textbooks, and is well known.

And the amount of resistance given by a column in the dynamic snapthrough is very slight, and is made even worse if it is acting over a long length column. Column breakage at the connections would give less resistance to the falling mass than buckling. All this is also very well known to qualified structural engineers.

If you have any engineering study that reutes this, then please present it.

Your answers never satisfy, never explain, never have proof

That depends on the audience. If a truther will not listen, then there is zero proof that will change his/her mind. This is anecdotal, but well demonstrated.

Fires above cannot cause the total and simultaneous failure of all major beams below.

Another strawman.

Fires weakened the first floors that failed only. Their kinetic energy destroyed the floors that they fell onto.

Engineering facts explain the reason why long, unbraced columns will buckle.

If you have any engineering study that reutes this, then please present it.

How anyone can defend the official story with a straight face is beyond me.

Maybe it's because my views depend on engineering facts?

Truther views depend on incredulity, not understanding engineering nor physics, and using this to construct in their little pea brains strawman arguments that have nothing to do with what the NIST report, nor accepted engineering theory say.

[edit on 29-6-2010 by Joey Canoli]

[edit on 29-6-2010 by Joey Canoli]

reply to post by iamcpc


I think it is possible to become too focussed on physics issues.

As you say, WTC 7 was not hit by an aircraft but it went down. NIST concluded that it went down as a result of fires which were initiated by the collapse of WTC 1.

I would suggest to you that if there was an insider plot to destroy WTC 7 then surely the conspirators would have planned a trigger for that collapse. It would appear, in fact, that no such trigger was planned. It was by pure chance that debris from WTC 1 damaged the building and set fires. No perps could have planned for that happenstance.

Apparently then, if people believe WTC 7 was brought down by controlled demolition, then they must believe that the perps intended to bring it down willy nilly with the world watching. I do not think that is credible.

In addition, the only reason I have seen put forward as a reason for the destruction of WTC 7 is that it contained secrets. Can anyone suppose that blowing up a building so that its contents can be distributed over half Manhattan is the optimum solution.

Originally posted by Alfie1
reply to post by iamcpc

 

I think it is possible to become too focussed on physics issues.

I don't know the whole conspiracy behind the wtc demolition theories. I've read it was the government, the CIA, the mossad, the zions, etc etc etc.

I only know that the independant investigations about the twin towers I have found presented very strong evidence that the twin towers collapse was not physically IMPOSSIBLE. I have not done enough research to come to any sort of conclusion about what was or was not IMPOSSIBLE in regards to WTC 7. The analsis of the twin tower impacts and collapse were more thorough because we have pretty decent estimations of

1. What hit the towers.
2. How fast it was going.
3. How much it weighed.
4. What direction it was going.
5. How much damage was done by the impact.

In WTC tower 7 I ask the same questions and have not been able to find the answers.

1. What hit the wtc7? Was it concrete? was it part of the wall? Was it a bunch of large steel beams?
2. How fast was it going?
3. How much did it weigh? 1 ton? 283 tons? 500 pounds?
4. Was it falling twoard the building or falling straight down onto part of the building?
5. How much damage was done by the falling debri? Was it almost cut in half? There was reports of a large gash. How large? how deep? why were pictures not taken?




I think that you can't become too focused on physics when a few people are saying things like it's physically impossible for the twin towers to have collapsed from airplanes and fire and thousands of people believe them. Then you must look at the physics. Math and physics simply can not lie. They can only be misinterpreted.

I was convinced, very briefly, that the twin towers collapse without the use of _____________(explosives, bombs, paper, thermite, thermate, micornukes, death star, energy guns etc) was physically IMPOSSIBLE. Then I started researching, I came to these forums, I found new sources of information, and then, when discussing the physics with ANOK, came to the understanding that a lot of the claims that the twin tower collapse was physically IMPOSSIBLE without explosives or nukes or death star lazer beams were based on incorrect assumptions like the twin towers fell at free fall speeds.

A perfect example of how the path of least resistance involves crushing the support structure.

www.break.com...

Originally posted by iamcpc
A perfect example of how the path of least resistance involves crushing the support structure.

www.break.com...

I was not going to reply to your brand of illogic anymore, but I had to reply to this just to dcorrect you, once again.

The top blocks of the towers, above the strike zone, began to drop virtually straight down after a series of explosions and fire belched out from just below the ' block'.

The ' blocks' comprising a number of floors, never crushed anything.

The photographic evidence CLEARLY, and unequivocally, shows that the blocks were ' dustified' or pulverized, as it entered the zone that was the top part of the structure below the strike zone.

The massive clouds of fine dust were generated from this event. it is plain to see. it is not debateable. After the block sections are pulverized,the rest of the Tower erupts and peels apart and hurls steel beams and clqadding far from the furthest point that gravity could possibly take it.

If what you imagine, and for which there is NO evidence, is that the top section hammered down the remaining tower until it stopped at the bottom, that is insane. If that were true, there would have been a block sitting on top of a huge pile of debris, very little of which would be dust.

There are NO...ZERO...NONE..large sections of building left. Not any blocks of floors, nor ant remnant of a floor except shredded steel and concrete as fine as face powder.

Until you begin with a correct assumption, you cannot arrive at a valid result. Your entire premise is wrong....there is total proof that the Towers ERUPTED at the level of the strikes, and as the block drops and enters that 'zone' it turns to dust, erupting UPWARDS and OUTWARDS with GREAT velocity. As the last part of the block enters the zone, that being the roof, the remaining column erupts aas well and shreds all the way down until there is only a 3 story debris pile...from over 100 floors..

You official story believers really have some nerve..it is like being a flat earther and being serious about it...delusional.

reply to post by Bob Sholtz


The problem is they fail to understand the basic laws of physics.

Mainly, in this case, that colliding objects have equal force not matter if one is moving, and thus the object with the least mass will receive the most damage due to the forces causing it to decelerate faster than the object with the most mass.

All speed does is increase the forces on BOTH objects, not just the one moving.

Originally posted by richierich

I was not going to reply to your brand of illogic anymore, but I had to reply to this just to dcorrect you, once again.

The logic of physics! Lets play (again) the twin towers physics game!
Lets do the math! Lets play the 9/11 physics game!
My brand of illogic involves PHYSICS!

Sources cited here:
www.abovetopsecret.com...

1 pound = 0.45359237 kilograms

a 110-150 ton 500 mile per hour airplane.

a 100,000 - 136,000 kg airplane Is traveling at 223 m/s

F=MA 2.23 million netwons of force.

355,00 newtons per square meter is the yeild strength of structural steel.

the wtc towers were 110 stories

450k TONS (total weight) / 110 stories = 4000 tons per floor.


The top 1/3rd of the WTC weighed about 120000 tons.

120k tons is 109,000,000 KG. falling downward at 9.8 m/s is

1,068,200,000 newtons = estimate of the amount of force in the falling top 1/3rd of the tower

2,230,000 newtons= estimate of the amount of force in the plane

1,068,200,000 / 2,230,000= 479 times the amount of force!!

If you hit each floor of the WTC with 4 110 ton 500 mile per hour airplane what would it look like????

A big pile of rubble!

The top blocks of the towers, above the strike zone, began to drop virtually straight down after a series of explosions and fire belched out from just below the ' block'.

Explosions huh?
Lets compare and contrast
www.youtube.com...
www.youtube.com...

www.youtube.com...
www.youtube.com...

BOOM BOOM BOOM BOOM BOOM BOOM BOOM BOOM BOOM

Those are some amazing SILENT explosives in the twin towers.

The photographic evidence CLEARLY, and unequivocally, shows that the blocks were ' dustified' or pulverized, as it entered the zone that was the top part of the structure below the strike zone.

The massive clouds of fine dust were generated from this event. it is plain to see. it is not debateable. After the block sections are pulverized,the rest of the Tower erupts and peels apart and hurls steel beams and clqadding far from the furthest point that gravity could possibly take it.

www.youtube.com...

fine dust clouds from a building that collapsed! Was this one demolished with explosives?

(also no BOOM BOOM BOOM BOOM BOOM BOOM)

You official story believers really have some nerve..it is like being a flat earther and being serious about it...delusional.

This is coming from the guy that things that silent explosives are strong enough to launch steel beams.

This is coming from the guy who believes that if you hit every single floor of the WTC towers with 110-150 ton 500 mile per hour airplanes that there would be big pieces of the building left!

You honestly believe that the Journal of Engineering Mechanics, the Journal of Structural Engineering, the Journal of Performance of Constructed Facilities, the Practice Periodical on Structural Design and Construction, the American Society of Civil Engineers, the Civil Engineering staff at the most prestigious engineering university on the planet, Massachusetts Institute of Technology, as well as all the other universities Northwestern and Perdue are all delusional for being OS believers???

sources cited here:

www.abovetopsecret.com...





So you believe all the journals and and schools listed above are delusional.



You honestly believe that someone snuck and installed silent explosives in the twin towers, in the middle of new york, in occupied buildings, without anyone knowing?



You honestly believe that, the people who installed the silent explosives, waited untill the buildings were on every news channel in america before detonating them?



Hmm guys we can demolish the twin towers now with no one watching and just say it was a terrorist bombing or we can wait untill they get hit by airplanes and demolish them with 200 million people watching!

Great idea! Let's keep it a secret by doing in front of 200 million watching people!! YEAH!!




I LOVE replying to your brand of illogic it's soooo funny!

A silent explosive launching steel girders!

Originally posted by ANOK

Mainly, in this case, that colliding objects have equal force not matter if one is moving, and thus the object with the least mass will receive the most damage due to the forces causing it to decelerate faster than the object with the most mass.

All speed does is increase the forces on BOTH objects, not just the one moving.

LOL your post just makes it clear that you don't understand. You give the example of an object resting on a floor with 9.81 newtons of force and a floor that is able to support 9.81 newtons of force.

In the collapse of the twin towers the top portion fell with about 1,068,200,000 newtons of force onto something that could support 71,123 newtons of force (assuming the floors could support 6 times their own weight. )

1,068,200,000 / 71,123= 15 thousand times the force the floor can support.





What happens when an object drops with X newtons of force and hits an object that can supprt 1/15,000 X newtons of force?

(keep in mind that 1,068,200,000 newtons is equal to hitting each floor of the twin towers with 4 airplanes)

Originally posted by iamcpc

(assuming the floors could support 6 times their own weight. )

Actually, this is a truther distortion.

NIST reported that the support connections could hold 6x the normal floor weight

The connections only.

This does NOT mean that the floors could hold 6x. The floors would fail LONG before that.

reply to post by iamcpc

Hey I'd take any of the first three over number 4 ! You can't be serious surely ? Get real !

Originally posted by iamcpc
LOL your post just makes it clear that you don't understand. You give the example of an object resting on a floor with 9.81 newtons of force and a floor that is able to support 9.81 newtons of force.

In the collapse of the twin towers the top portion fell with about 1,068,200,000 newtons of force onto something that could support 71,123 newtons of force (assuming the floors could support 6 times their own weight. )

1,068,200,000 / 71,123= 15 thousand times the force the floor can support.

No, no, no, once again you fail to understand, this is getting old really fast mate.

The diagram shows that the force of the weight hitting the ground puts equal force on the ground and the weight which is in this case 9.81 N.

Your claim for the forces during the collapse come from where? Where is your proof any floors fell at all? The visual evidence alone proves this wrong, but we all know you don't understand visual evidence, you just proved that with the diagram you misunderstood.

Anyone else not understand what this is showing?...



Look at the little up/down arrows imapcp, see what it says, 'force of gravity', 'reaction of the floor'. It shows a 1kg weight impacting the ground and forces acting on the floor and the weight, which are equal, 9.81N.

It shows Newtons 3rd law, for every action there is an EQUAL and opposite reaction, and The Law of Momentum Conservation.

Read this it says exactly what I've been trying to explain to you (since you asked by U2U).

The Law of Action-Reaction (Revisited)

A collision is an interaction between two objects which have made contact (usually) with each other. As in any interaction, a collision results in a force being applied to the two colliding objects. Such collisions are governed by Newton's laws of motion. In the second unit of The Physics Classroom, Newton's third law of motion was introduced and discussed. It was said that...

... in every interaction, there is a pair of forces acting on the two interacting objects. The size of the force on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs...

...Newton's third law of motion is naturally applied to collisions between two objects. In a collision between two objects, both objects experience forces which are equal in magnitude and opposite in direction. Such forces often cause one object to speed up (gain momentum) and the other object to slow down (lose momentum).According to Newton's third law, the forces on the two objects are equal in magnitude. While the forces are equal in magnitude and opposite in direction, the acceleration of the objects are not necessarily equal in magnitude. In accord with Newton's second law of motion, the acceleration of an object is dependent upon both force and mass. Thus, if the colliding objects have unequal mass, they will have unequal accelerations as a result of the contact force which results during the collision.

www.physicsclassroom.com...

Now tell me I'm making things up!

[edit on 6/30/2010 by ANOK]

Originally posted by Joey Canoli

Originally posted by iamcpc

(assuming the floors could support 6 times their own weight. )

Actually, this is a truther distortion.

NIST reported that the support connections could hold 6x the normal floor weight

The connections only.

This does NOT mean that the floors could hold 6x. The floors would fail LONG before that.

Again where are you getting this from? You guys always scream for resources where are yours for all these claims you keep making?

What part of the floors would fail if according to your normal argument that the welds would be weak spots? The middle, the edges?

You know the floors were one steel pan filed with concrete right?

Now how about you explain to us exactly what you mean by the floor would fail before the connections, and where did you get the info from that showed you the load capabilities of floors and connections?

I'd love to see it because so far I have been very conservative and using the common FOS of 2x, if it turns out it is 6x, quite probable, then it makes the OS all the more ridiculous. If the building was designed with a safety factor of 6x that means it could hold 6x it's own weight before failure even begins to happen. If the steel lost 50% of it capacity to hold itself up that would still mean it could hold 3 times it's own weight...

Buildings commonly use a factor of safety of 2.0 for each structural member. The value for buildings is relatively low because the loads are well understood and most structures are redundant.

en.wikipedia.org...

Do you know what 'redundant' means in the context of a building? It basically means it can lose most of it's structural components and still remain standing, the load capacity for each component can be relatively low because the design, how the components are arranged and joined, makes the system redundant. This is why buildings do not generally completely collapse from asymmetrical localized damage, especially over-engineered buildings like the towers.

Buildings are not designed to just about hold themselves up, add a another floors and the lot will come down. You could place at least one more WTC tower on top of the existing structure and it wouldn't collapse under the weight. The weight of a 757 is not going to be anything the building could not hold up easily.

An empty 757 weighs only 127,520lb, what did the WTC weigh?

www.airliners.net...

[edit on 6/30/2010 by ANOK]

Originally posted by ANOK
No, no, no, once again you fail to understand, this is getting old really fast mate.

ditto

The diagram shows that the force of the weight hitting the ground puts equal force on the ground and the weight which is in this case 9.81 N.

What happened in the collapse of the twin towers is that the top portion of the building fell with X newtons and the lower floor that it impacted with could only support 1/1500th X newtons of force.

Your claim for the forces during the collapse come from where?

scroll up. I even cited my sources.

www.abovetopsecret.com...

6/30/2010 @ 4:41 pm.

Since you didn't read it i'll even copy and paste it for you in addition to citing my source.

1 pound = 0.45359237 kilograms

a 110-150 ton 500 mile per hour airplane.

a 100,000 - 136,000 kg airplane Is traveling at 223 m/s

F=MA 2.23 million netwons of force.

355,00 newtons per square meter is the yeild strength of structural steel.

the wtc towers were 110 stories

450k TONS (total weight) / 110 stories = 4000 tons per floor.


The top 1/3rd of the WTC weighed about 120000 tons.

120k tons is 109,000,000 KG. falling downward at 9.8 m/s is

1,068,200,000 newtons = estimate of the amount of force in the falling top 1/3rd of the tower

2,230,000 newtons= estimate of the amount of force in the plane

1,068,200,000 / 2,230,000= 479 times the amount of force!!

If you hit each floor of the WTC with 4 110 ton 500 mile per hour airplane what would it look like????

A big pile of rubble!

Sources cited here www.abovetopsecret.com...

Where is your proof any floors fell at all? The visual evidence alone proves this wrong, but we all know you don't understand visual evidence, you just proved that with the diagram you misunderstood.

URL=http://img404.imageshack.us/i/wtc.png/][/URL]

the visual evidence proves that the top portion is not falling? That's a pretty good fake picture! But clearly you know the top portion is not falling. It must be floating! You believe the top portion is not falling and i'm the one who does not understand the visual evidence?





What happens when an object is falling with 15,000 newtons of force and it impacts an object that can support 1 newton of force?





[edit on 1-7-2010 by iamcpc]

Originally posted by ANOK

Again where are you getting this from?

Did you not see the part where I said "NIST reported"? Rational people, with at least a kindergarten level of reading comprehension, could ascertain that I got it from the NIST report.

What part of the floors would fail

The whole floor. Trusses. Concrete. Etc. They were designed to hold 150 psf. Only a lunatic would dispute that they couldn't carry 900 psf.

if according to your normal argument that the welds would be weak spots?

Liar.

Now how about you explain to us exactly what you mean by the floor would fail before the connections

The floor would fold up, the concrete would break, and the trusses would yield.

and where did you get the info from that showed you the load capabilities of floors and connections?

NIST report. They got the floor design load from original documents. They're reproduced in the report. that's why you're confused about how anyone could know this.Cuz you've never read it.

I'd love to see it because so far I have been very conservative and using the common FOS of 2x

First reasonable thing you've said.

if it turns out it is 6x

It's not. This is the FOS for the floor connections ONLY, not the whole building. If you had actually researched any, you'd know the difference.

You could place at least one more WTC tower on top of the existing structure and it wouldn't collapse under the weight.

You're insane if you believe that.

You could neither go twice as high, nor have twice the weight.

You're just talking out of your backward facing orfice.

reply to post by iamcpc


That is NOT proof floors were falling on floors. The top section was turning to dust as it fell, you can not see inside and see solid one piece floors dropping on other floors. Assumption not based on any evidence or facts, known physics would argue that to be near impossible, so why choose the most extreme outcome as the only possibility as to what happened?

If floors did drop as one piece on floors, it's not because of an hours worth of fires. You are seeing the result of some other energy acting on the building, whatever that was.

Sorry but the visual evidence shows the top section collapsed on it's own before the bottom started to collapse...




heiwaco.tripod.com...

If the top collapsed before the bottom how did the top cause the bottom to be crushed down to it's foundations? The top is almost gone before the bottom goes. Same thing with WTC 2, you keep forgetting the tilt and the fact that a tilting object, look up angular momentum, cannot suddenly change it's mind and crush symmetrically what's underneath it.

And again you ignore basic physics, in that colliding objects all receive equal force, so the force of the top hitting the bottom would be the same, remember the weigh illustration you failed to understand?
So were does the extra energy come from to cause the top to turn to dust and then crush the rest of the building to it's foundations. If you didn't notice that top section does not stay as a solid block all the way down crushing the building and sitting on top of the debris pile. Did the top continue crushing itself when it finished crushing the bottom?

www.physics4kids.com...

[edit on 7/2/2010 by ANOK]