Here is what a building falling from structural failure looks like.

Originally posted by Steel Penguin
I know. I asked you how you know that buildings only collapse in their own footprint by demolition?

Because any object that is dropped will take the path of least resistance. Thousands of tons of construction steel, bolted and welded together forming a super strong structure that could stand by itself, is not the path of least resistance. When an object collides with another more solid object, or of similar strength, it will fall to one side (just as WTC 2 started to do until 'something' took out the floors bellow the damaged area).

We don't have to have seen this happen to know what a building would do, we only need to apply some basic principles of physics.

Originally posted by ANOK

We don't have to have seen this happen to know what a building would do, we only need to apply some basic principles of physics.

true, but someone said people should demonstrate what buildings actually fall like for real when presented with the circumstances of structural failure so,

voila.

Originally posted by selfless

Originally posted by ANOK

We don't have to have seen this happen to know what a building would do, we only need to apply some basic principles of physics.

true, but someone said people should demonstrate what buildings actually fall like for real when presented with the circumstances of structural failure so,

voila.

Which is why i asked what the structural failures were of the building you posted?

That seems fair enough ANOK. I don't know enough about engineering and physics to really add anything relevant.

I only question these "facts" reported by some because i haven't made a decision as to what really happened on 9/11. Both sides of the story seem to have more holes then a collinder (sp).

To quote Carl Sagen on this one, extroadinary claims require extroadinary proof. IMO both sides have failed in that regard.

The easiest way to explain the physics of what happens when a building collapses is this.

Remember those cartoons where the woodcutter chops down a tree, shouts "TIMBER" and the tree collapses?

What does he do? He chops out a wedge shape in the trunk of the tree, and then a gentle push from the other side is enough for the tree to collapse in the direction of the wedge, right?

In the case of a building, like the one in the video above, the wedge, or the failure, appears to be near the base, quite possibly even the foundations.

Note how the top of the building travels quite a long way, horizontally. That's because, just like the tree, we haven't pulverized the tree, the whole trunk is still attached to itself, so the top of the tree falls a long way, ending up roughly the entire length of the tree away from the tree stump, maybe even a little more than that.

The planes hitting the WTCs, were essentially cutting a wedge in the support of the towers on one side. Again, just like the tree analogy. By rights, therefore, when the building began to fall, the top of the building should rotate around that wedge point of collapse. Imagine, in any situation like this, that the "missing chunk" of your tree, your building, whatever, is the center of a clock face, with the upper part of the object being the hand, originally at 12 o clock. You're not going to get precise rotational motion in all cases, but it's pretty accurate to assume that that roughly would be the case.

Now, imagine that you have winds acting on the building, and gravity.. So you have a horizontal force, and a vertical force. Can you imagine your tree, if you chop a big wedge out of it maybe 2/3 of the way up.. Push on the other side. Or don't, put ANY forces on it that you would like, tell me how it falls?.. Does it *ever* fall straight into the tree trunk? Put as much weight on top of your imaginary tree as you like. Build the biggest tree house in the world on there, does it fall into the tree trunk yet?

Do you see now why a gut sense of the physics involved here just seems wrong?. Yes, buildings are not like trees, there are obviously huge differences, however, in terms of the physics here, I wanted an example that would be easy for anyone, even those without a background in science, to visualize.

damn look at that dustification. every building (regardless the dimensions) has to collapse like this one or else it was a CD.

Originally posted by Inannamute
The easiest way to explain the physics of what happens when a building collapses is this.

Remember those cartoons where the woodcutter chops down a tree, shouts "TIMBER" and the tree collapses?

What does he do? He chops out a wedge shape in the trunk of the tree, and then a gentle push from the other side is enough for the tree to collapse in the direction of the wedge, right?

In the case of a building, like the one in the video above, the wedge, or the failure, appears to be near the base, quite possibly even the foundations.

Note how the top of the building travels quite a long way, horizontally. That's because, just like the tree, we haven't pulverized the tree, the whole trunk is still attached to itself, so the top of the tree falls a long way, ending up roughly the entire length of the tree away from the tree stump, maybe even a little more than that.

The planes hitting the WTCs, were essentially cutting a wedge in the support of the towers on one side. Again, just like the tree analogy. By rights, therefore, when the building began to fall, the top of the building should rotate around that wedge point of collapse.

Except that the WTC did not collapse when the planes hit. They collapsed after an hour or two of a raging fire heating up structural elements over a wide area, including an area of severe damage from the impact.

The building in that video is much much smaller than the WTC.

The dynamic load of a dozen floors of a WTC just fallling one or two floors, impacting the weakened part below probably created a catastrophic structural failure all throughout the lower part of the building.

Imagine, in any situation like this, that the "missing chunk" of your tree, your building, whatever, is the center of a clock face, with the upper part of the object being the hand, originally at 12 o clock. You're not going to get precise rotational motion in all cases, but it's pretty accurate to assume that that roughly would be the case.

Now, imagine that you have winds acting on the building, and gravity.. So you have a horizontal force, and a vertical force. Can you imagine your tree, if you chop a big wedge out of it maybe 2/3 of the way up.. Push on the other side. Or don't, put ANY forces on it that you would like, tell me how it falls?.. Does it *ever* fall straight into the tree trunk? Put as much weight on top of your imaginary tree as you like. Build the biggest tree house in the world on there, does it fall into the tree trunk yet?

Do you see now why a gut sense of the physics involved here just seems wrong?. Yes, buildings are not like trees, there are obviously huge differences, however, in terms of the physics here, I wanted an example that would be easy for anyone, even those without a background in science, to visualize.

The remaining part of the treetrunk can hold up the tree better than the remaining part of the WTC could after the top South Tower tilted a bit and probably nearly severed everything. The WTC is so much heavier.

The South tower tilted a little bit before the collapse, the North, not much at all. The north was also damaged from the collapse of the South.

The buliding in the video also started out tilting. The WTC did not.

The early 90's WTC bombers wanted to blow up the supports underground on one side to get one tower to fall into the other. They almost did it---with just a bigger bomb it might have happened. Two jets were bigger bombs.

Regardless of what brought down the WTC towers, the building in that video doesn't shed much light on their collapse. That building was much smaller, for one thing, and things don't necessarily scale upward in ways that are intuitive. More important than the scaling question, though, is the fact that the building in this video isn't built the way the WTC towers were built, and wasn't damaged in a way similar to either the 'official story' or to a controlled demolition. In short, you have totally different damage, applied to a totally different structure...which means that the amount of relevant data you can come up with is near zero.

One thing I do want to know...where were the "4th generation micro-nuclear warheads" in this building? After all, that's the only explanation for those clouds of grey dust boiling away from the WTC...and I could *swear* I saw clouds of grey dust billowing out from the collapse of this building too.

Why do some members of this board insist upon bringing up the most extreme examples of conspiracy theories in a discussion which does not mention them at all? The place for discussing those theories is in the relevant threads devoted to them. If every thread degenerates to an attempt to debunk every single theory, it becomes pointless to even have separate threads.

As far as the collapse - the only way for the building to have the dynamic impact of the floors being the reason it collapsed straight down is for every structural element on however many floors that fail to collapse simultaneously - in my tree analogy, this would be us coming along with a big fat chainsaw, and swiping it all the way through the trunk.

I'd really love to see some finite element analysis of the collapses done, where someone built the towers according to blueprints and accurate load figures, and then repeatedly knocked out columns until they got a collapse identical to either tower one or two...

I find it interesting that many posters over the last couple of days have cited the bridge collapse as being proof that the official theory of WTC collapses is correct, but yet a building collapse video has no relevance?

You can sit there and say "Ok, it doesn't look like a controlled demolition, and it doesn't look like the wtc collapse, therefore it's irrelevant", but in fact, I think that's the point the original poster was trying to make.. It's a building failing structurally which collapses. Previously on this board there have also been posts of buildings failing due to fires. None of these look like the WTC collapses. That's the point. The WTC collapses are "unique" in history.

Innamute,

Uh, excuse me, but if you're going to argue about the WTC on 9/11, at least get your nomenclature straight.

It wasn't "collapse." It was explosion. Those buildigns simply were blown up. End discussion.

Think of those grey chrysanthemum plumes ejecting sizzling steel girders a couple hundred feet...

And indeed, basic physics--heck, basic common sense--tells you that a huge re-enforced steel frame structure (especially one that doesn't retain its structural integrity but instead explodes as it falls--is going to take the path of least resistance, which is to topple over.

The WTC exploded.

So really.

I'm sorry, but I prefer to make my own decisions on the words I use, rather than letting other people choose them for me.

I like to actually use my brain for things other than holding my ears apart, and I think that making value judgements on the mechanism of collapse when I can't prove what I think happened is the worst form of intellectual arrogance.

A theory is just a theory, until it is proven.

I've yet to prove a theory, so I will stick with the most neutral words I can.

Thanks for your input.

Originally posted by mbkennel
The remaining part of the treetrunk can hold up the tree better than the remaining part of the WTC could after the top South Tower tilted a bit and probably nearly severed everything. The WTC is so much heavier.

The South tower tilted a little bit before the collapse, the North, not much at all. The north was also damaged from the collapse of the South.

Weight is irelevant. The building was constructed, just like all buildings, to carry its own weight plus some. It's a safety facter, and all architects take this into consideration when designing a building.

South Tower didn't tilt that much?



Please explain to me how the inertia of the top was changed?

The top should have continued it's motion, as in 'Newtons 1st laws of motion' (Inertia) and the 'law of conservation of angular momentum.'

Objects executing motion around a point possess a quantity called angular momentum. This is an important physical quantity because all experimental evidence indicates that angular momentum is rigorously conserved in our Universe: it can be transferred, but it cannot be created or destroyed.

What energy caused the angular momentum to stop and transfer to vertical momentum?

A body at rest remains at rest, and a body in motion continues to move in a straight line with a constant speed unless and until an external unbalanced force acts upon it...An object that is in motion will not change velocity (accelerate) until a net force acts upon it.

What was that external unbalanced force? Gravity isn't the answer. I think we can all agree that the lower undamaged floors had the energy to hold the mass of the top. From what I've read the WTC was designed to take 2.5 times it's own mass. So what force caused the top, which was in motion, to change it's velocity?

How does aprox 20% of mass overcome and destroy the other 80% by gravity alone, especially when it wasn't sitting true at the start of the collapse, yet all four corners fell at the same time.

Have you even thought about these things? Or are you just here to rigorously deny anything that contradicts the official story any way you can? Lots of new people this week espousing the same uneducated garbage in the hope something will stick. 'They' must be getting desperate...

[edit on 1/5/2007 by ANOK]

Please note that i only posted the video to show in what manner a building from structural failure would fall.

It would not fall like a pancake.

Originally posted by ANOK

How does aprox 20% of mass overcome and destroy the other 80% by gravity alone, especially when it wasn't sitting true at the start of the collapse, yet all four corners fell at the same time.

[edit on 1/5/2007 by ANOK]

Yes, that is extremely well said.

If it was the 80% that fell onto a 20%, the 80% would still fall on the side after impact with the remaining 20%. It would certainly not pancake.


[edit on 2-5-2007 by selfless]