Yep, It's Thermite! So Much for the "Oxygen" Excuse

Originally posted by exponent
This is where you make a mistake. What you are assuming here is that the mass is accelerating horizontally throughout its entire fall, which is not the case. In fact the unit suffers an initial violent acceleration until it is ejected from the building, and a deceleration due to air resistance afterward.

That's exactly what I said:

Originally posted by bsbray11
The horizontal component in reality did not accelerate over time, but was imparted with an initial velocity from a force and then just sailed out into the air, only having air to resist it, until it hit the ground.

In fact what you need to divide is the average speed. 150m in 9 seconds is an average speed of 16 2/3m/s.

If you average in the original acceleration from rest (whether it happened in a split second) to the acceleration when it had already reached its final velocity (relatively speaking) it makes no difference in terms of total energy used to get there in the total amount of time.

The acceleration could also change the entire time the object is falling, and if it still hit the ground at a distance of 150m laterally from where it started, and it still took 9 seconds to do it, then all its accelerations would STILL average out to the figure I posted. That's just how the numbers work mathematically, unless I have made a mathematical error, and the numbers can't work out with any other acceleration figure.

The problem is that we don't know how long the force was exerted to eject the mass but let us take a ballpark figure of 0.2s. This gives us the following formula to put into the simple equations of motion: en.wikipedia.org...

u=0
v=16.7
t=0.2

v = u + at or 16.7 = 0.2a
which can be rearranged as
a = 16.7/0.2

This gives us an acceleration of 83.3m/s/s requiring force 907*83.3=75,553.1N.

You just implied that the 1-ton mass accelerated at 83m/s^2. If you worked out the rest of the numbers around that, I'm pretty sure you would find it wouldn't work out quite the same as what I did above. That force can't be applied over the whole 9 seconds it took for the debris to hit the ground, so you are measuring a different force than I am. You need to use the average acceleration of the whole time period I am looking at, not just the acceleration for the 0.2 second period only.

Given d=150m, t=9s, and no initial velocity, then a=3.7m/s^2 is the ONLY solution that satisfies d=v0+( (1/2)a(t^2)). Even if that average acceleration does not accurately reflect the actual acceleration, it still relates to energy as if it does in the formula.

This is not a gigantic amount of force, using the ballpark of 10N = 1kg, this is the same as a weight of 7.5 tons. The upper sections of each tower weighed in the region of a hundred thousand tons.

You forget that 80%-90% of the masses of both towers were ejected in this way, not just isolated pieces:



So the energy required to send all this debris flying outward would have added up very rapidly, not to mention all that mass can no longer contribute to crushing the tower down further and further anymore. And yet the collapses continued as if it didn't even matter.

[edit on 9-6-2009 by bsbray11]

I would say both your claims are wrong. NIST primary purpose was to determine the causes of the collapses, not to disprove anything. Employing the scientific method, their conclusions precluded the controlled demolition theory. And separately NIST investigators addrssed the claim of controlled demolition and possibility of thermite being used.

A summary below of NIST questions and answers, including the thermite claim.

What? They used the scientific method yet precluded the cd theory? That is a contradiction before you go any further. Also, the fact that they admit they disregarded evidence is another strike. Add to that the fact that they did not re-hypothesize when the data set failed and simply created a new data set (8 more times after that) is another strike.

The NIST report did not in fact determine the cause of the collapses. It determined that the pancake collapse could have been initiated under the circumstances with manipulated data.

Originally posted by jprophet420

The NIST report did not in fact determine the cause of the collapses. It determined that the pancake collapse could have been initiated under the circumstances with manipulated data.

I'm a spokesman for NIST, but don't find their revisions suspicious nor do I think there was withholding of evidence to conceal significant data.

There are many claims of what NIST did and didn't do, about their biases, intent, hidden agenda, etc. They were tasked to find the cause of the collapses which they ultimately did satisfactorily.

From their own website they which includes information on findings NIST investigators made beyond the report, they reject the pancake theory and address the controlled demolition scenario, even mentioning the missile claim.

I'm not sure how many people know what NIST did and did not say, and how many base their knowledge on claims made against them.

I recommend the page below as it addresses many of the questions raised about their report.

wtc.nist.gov...

NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers
[...] Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.

NIST’s findings also do not support the “controlled demolition” theory..

[...]

Video evidence also showed unambiguously that the collapse progressed from the top to the bottom, and there was no evidence [...] of any blast or explosions in the region below the impact and fire floors as the top building sections (including and above the 98th floor in WTC 1 and the 82nd floor in WTC 2) began their downward movement upon collapse initiation.

In summary, NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to Sept. 11, 2001. NIST also did not find any evidence that missiles were fired at or hit the towers. Instead, photographs and videos from several angles clearly show that the collapse initiated at the fire and impact floors and that the collapse progressed from the initiating floors downward until the dust clouds obscured the view.

Mike



[edit on 9-6-2009 by mmiichael]

Originally posted by bsbray11
That's exactly what I said:

I guess I missed that!

If you average in the original acceleration from rest (whether it happened in a split second) to the acceleration when it had already reached its final velocity (relatively speaking) it makes no difference in terms of total energy used to get there in the total amount of time.

As long as the final velocity is identical then the equation for kinetic energy will still be the same, but we know that a force was not applied throughout the entire fall, it was in fact applied only at the beginning. No force can apply 8kN horizontally to an object flying through the air but we have a good explanation of why the building would impart 75kN for a short period during collapse.

You just implied that the 1-ton mass accelerated at 83m/s^2. If you worked out the rest of the numbers around that, I'm pretty sure you would find it wouldn't work out quite the same as what I did above.

Well no, it doesn't, KE is the same but the actual force applied is not.

That force can't be applied over the whole 9 seconds it took for the debris to hit the ground, so you are measuring a different force than I am.

Exactly, there is no reason to suppose that the object accelerates once it has left the tower (in a horizontal direction) and so it will in fact have experienced a much larger initial force.

You need to use the average acceleration of the whole time period I am looking at, not just the acceleration for the 0.2 second period only.

Why?

You forget that 80%-90% of the masses of both towers were ejected in this way, not just isolated pieces:

Where is the information that indicates 80-90%? I think it's more likely it was 30-40%.

So the energy required to send all this debris flying outward would have added up very rapidly, not to mention all that mass can no longer contribute to crushing the tower down further and further anymore. And yet the collapses continued as if it didn't even matter.

There is no magic behind this, as I'm sure you are aware, Dr Greening, Dr Bazant et al have done excellent work on identifying the required energy to fail the towers. We can go into that if needed but this is not the thread.

Originally posted by exponent
As long as the final velocity is identical then the equation for kinetic energy will still be the same, but we know that a force was not applied throughout the entire fall, it was in fact applied only at the beginning.

I never mentioned velocity or KE. What I just calculated was net force and work to displace a ton mass 150m. Simple. The math is above. Have YOU had physics before?

No force can apply 8kN horizontally to an object flying through the air but we have a good explanation of why the building would impart 75kN for a short period during collapse.

You could still work out an acceleration within 0.2 seconds and have all the accelerations of the 9 second period average to 3.7m/s^2. Again, this is the ONLY NUMBER that will satisfy the equation, given the other variables.

Exactly, there is no reason to suppose that the object accelerates once it has left the tower

I DON'T suppose that, you are reading things into my posts that I have obviously contradicted my own self. Stop scrambling to debunk something that was correct from the start. Some "truthers" know physics, get over it. The only acceleration you can use in a formula describing the force used over a 9 second period is the AVERAGE ACCELERATION over the SAME 9 second period!! You can't use an acceleration during 0.2 seconds for an entire 9 second period!! You wouldn't be calculating the same thing at all! An acceleration of 0 or a negative acceleration are also possible, these would be your accelerations AFTER the object was launched, and then it would still all average out to 3.7m/s^2. It has to, obviously, because of the way the formula works.

You need to use the average acceleration of the whole time period I am looking at, not just the acceleration for the 0.2 second period only.

Why?

Why don't you go ask your physics professor? If I was trying to calculate the net force exerted during the 0.2 seconds of actual acceleration of the mass, then you would be right. But I'm NOT. I'm calculating the amount of force/energy required to displace a 1-ton mass 150m over 9 seconds, which actually happened (actually I gave leniences as described in the first post). If you plug your enormous acceleration into the force equation then you are implying that acceleration was the average acceleration over the 9 second period, which is obviously false. I posted the formula above. Again, the ONLY number that will mathematically fit into that formula is 3.7m/s^2, because that IS the average acceleration of that period! Dude, I wasn't even TRYING to calculate acceleration, there is no need to obsess on that figure. When you prove my math wrong, talk to me about it.

You forget that 80%-90% of the masses of both towers were ejected in this way, not just isolated pieces:

Where is the information that indicates 80-90%? I think it's more likely it was 30-40%.

There is not 60%-70% of the mass of either tower still sitting in its footprint.

Debunked.

And no, it didn't go all into the basements. I could post photos of the excavation.

There is no magic behind this, as I'm sure you are aware, Dr Greening, Dr Bazant et al have done excellent work on identifying the required energy to fail the towers. We can go into that if needed but this is not the thread.

Frankly Dr. Greening is an idiot and I don't even like seeing his name thrown around as if he knows anything about what he's talking about. I am also aware of their energy calculations, and I'm sure YOU are aware of others' work that contradicts theirs. It's another case of fudging numbers until you get the result you want, not necessarily the one that is the most accurate reflection of reality, and if we got into the nitty gritty, the attitudes they adopted towards certain energy sinks would reflect this.

[edit on 9-6-2009 by bsbray11]

1. You're a spokesman for NIST with 2 warnings on this board? I don't want anyone to think this is a character attack but that directly reflects your level of professionalism.
2. While there are "many claims" as you put it, I refer to claims made within the document, not speculation.

In the NIST report they admit to excluding much of the evidence that could imply CD was used. This does not imply that CD was or was not used, however it is illustrates that the scientific method was averted. In other words admitting that the steel was shipped off and not tested rules out the possibility that an experiment was undergone to determine the chemical composition of the steel.

The second scenario I must point out is the computer recreations that showed the initiation of the collapse actually required several reworkings to bring the simulation to collapse initiation. This averts the scientific method in that no new hypothesis was cunstructed upon failure of the experiment.

And finally, I look at the trickery in the question that is being asked in the first place. The question I want to know is "Were the twin towers broght down by and as a direct result of the jetliners that crashed into them?" The question that the NIST asks is "Was it possible for the airliners to initiate global collapse?"

www.abovetopsecret.com...

Video evidence also showed unambiguously that the collapse progressed from the top to the bottom, and there was no evidence [...] of any blast or explosions in the region below the impact and fire floors as the top building sections (including and above the 98th floor in WTC 1 and the 82nd floor in WTC 2) began their downward movement upon collapse initiation.

There are 682 architectural and engineering professionals that say that information is incorrect, and analysis of the video footage shows that 10 out of 10 criteria are met for CD. If 10 out of 10 criteria are met then video evidence certainly does not "show unambiguously" anything.

unequivocal: admitting of no doubt or misunderstanding; having only one meaning or interpretation and leading to only one conclusion

For it to be unambiguous it would have to have met 0 out of 10 criteria. Thats by definition, not my opinion.

NIST concluded that the WTC towers collapsed because:

They concluded how the collapse could have been initiated in the report i read.

reply to post by bsbray11


Its funny. When you have a tall object, made up of numerous sections all connected together vertically, and when it starts to tip over, the sections at the top will be falling farther away than the lower ones. Now obviously we didnt have the entire wall 1,000ft+ all fall away in one piece, but sections fell apart some stayed connected together longer enough to fall farther away. The force which started the tipping over was the collapse of the top section falling down through the rest. See, NOW we can use a tree falling over comparison. When a tree falls over, what is accellerating the tree horizonatlly? If a really tall tower falls over, a steel radio tower for exp, what forces are acting on it to have it fall over? Gravity. However it will not fall straight down, but tip over and fall. Here I'll even post you an example of a chimney falling over to show this.



Now then pay attention to the topmost part of the chimney. Imagine the chimney as a section of the exterior columns about 4 sections tall. Where does it land? Do you see any explosives at the top of the chimney pushing it over in that direction? Now Im surprised you dont really understand this basic idea of objects falling over. The exterior columns during the collapse behaved in basically the same way as this chimney was falling over. However the difference is, the exterior columns were given the initial push out by the force of the collapsing top section. After that, the exterior columns just started peeling back and away.

Unless you would care to explain just how much explosive would have had to been inside eeach and every floor of the WTC to be able to catapult only selective sections of the exterior columns. Plus, the exterior columns weighed a lot, so exactly how powerful were these explsoves? Oh wait, I thought they were magic nano-thermites that were painted on in really really thin coats.

But I guess you would rather just use techno-jargon of physics to sound smarter and talk down to me, when in reality you really arent too sure what the heck is being said.

[edit on 6/9/2009 by GenRadek]

He used physics formulas and you used a you tube clip.

GG.

reply to post by GenRadek


Yeah, that doesn't really debunk what I posted, it just goes to further illustrate you're confused about what you're talking about. What you are repeatedly showing is a rotation about a fulcrum. None of the ejected pieces of debris were pivoting about a fulcrum, they were actually sailing through the air from a purely horizontal force imparted to them from some unknown interaction. That force is exactly what I just calculated, that you didn't even address, I guess because it went over your head.

Ask exponent about it, he's on "your side" and I'm sure he also understands this. Ask anyone else who has had a college physics class and had to actually work these kinds of problems to pass the class.

Originally posted by GenRadek
But I guess you would rather just use techno-jargon of physics to sound smarter and talk down to me, when in reality you really arent too sure what the heck is being said.

This is called projection in psychology. You project your confusion of what I am talking about onto me, because you are too arrogant to admit you don't know basic physics. I know exactly what I am saying. The problem is with you, but you won't even admit it to yourself. If I had to guess I would say you have never had a physics class.

[edit on 9-6-2009 by bsbray11]

reply to post by GenRadek


GenRadek, are you saying that there was a 350 ft section of the North Tower that performed like the red section in the following quick model?

reply to post by GenRadek


Wow...I think you've hit rock bottom. The towers didnt tip over. They collapsed into their own footprints. Where in the world do you see any steel beams 'peeling away'? Thats amazing.

Try again.


[edit on 9/6/2009 by P1DrummerBoy]

reply to post by bsbray11


I don't know why today you are suddenly so aggressive, but your understanding of the situation is incorrect as your equation is based on a continuous acceleration. Let me illustrate. In your example, the object accelerates continuously at 3.7m/s/s in one direction. Which, after 9 seconds of acceleration gives us a final speed of 33.3m/s. I apparently can't link to JREF's LaTeX script here so I will just put down the numbers and I am sure you won't have a problem with it.

E_k = 1/2mv^2 = 453.5 * 33.3^2 = 502881.615J = 502KJ

This number is not identical to your result, but within the margin of rounding errors.

However, we know that this did not actually occur! As you stated in reality the object experienced a brief period of rapid acceleration, and traversed the whole distance at a constant velocity. That velocity, (150/9) is the amount we need to calculate kinetic energy as follows:

E_k = 1/2mv^2 = 453.5 * 16.7^2 = 126476.615 = 126KJ

As you can see, your methodology, by incorrectly assuming the resultant velocity, overestimates kinetic energy by a factor of more than 3 and as we are both aware, in this context Work = difference in KE.

I don't mean this to come across as harsh or criticising, and I am unsure why you were so abrasive in your post to me, but you did get this wrong. The energy required to accelerate a section of the towers to travel 150m horizontally in 9 seconds while weighing 907kg is not 502KJ, it is 126KJ.

Originally posted by exponent
I don't know why today you are suddenly so aggressive, but your understanding of the situation is incorrect as your equation is based on a continuous acceleration.

Once again, no, it isn't. I'm going to stop explaining this, as you obviously aren't paying attention to what I am saying.

Given,

d=150m (TOTAL distance traveled)
t=9s (TOTAL time elapsed)
initial velocity = 0

Now solve this equation!:

d=v0+( (1/2)a(t^2))



Solve this equation for "a."

Go ahead and solve it given those variables yourself, and THEN let's talk about who is wrong.

However, we know that this did not actually occur! As you stated in reality the object experienced a brief period of rapid acceleration, and traversed the whole distance at a constant velocity.

Yes, as I stated. I am well aware of the fact, I stated it in the very first post on this subject, when you ignored it and assumed I was unaware of this fact. However, YOU are apparently ignorant to the fact that it DOES NOT MATTER when you are calculating the net force, because you have to use the AVERAGE acceleration OF THE WHOLE PERIOD OF TIME IN WHICH YOU ARE ANALYZING. NOT just the beginning, NOT just the end, BUT THE WHOLE TIME. Even if it accelerates very rapidly at first, afterwards its acceleration is going to be ~0 and even a NEGATIVE figure, and when you SUM THESE ACCELERATIONS for the whole time period, you get the AVERAGE ACCELERATION FOR THE WHOLE 9 SECONDS. Realize that I do not try to measure the acceleration directly but use the other variables and the given formula to find the average acceleration! Again I used THE FORMULA to find this number.

I could not be more clear than that. It sounds to me as if you're begging to join pteridine on my ignore list, but please, solve the equation I posted above for "a". Please please please solve it and tell me what number satisfies it! Then tell me the equation is wrong, or any of the variables I provide are not justified!

I'm not being aggressive, I am being ANNOYED at your ignorance of basic physics. Just solve the equation and tell me that the equation is wrong, or the numbers it generates is wrong.

[edit on 9-6-2009 by bsbray11]

Originally posted by exponent
However, we know that this did not actually occur! As you stated in reality the object experienced a brief period of rapid acceleration, and traversed the whole distance at a constant velocity. That velocity, (150/9) is the amount we need to calculate kinetic energy as follows:

E_k = 1/2mv^2 = 453.5 * 16.7^2 = 126476.615 = 126KJ

Bear in mind that this is for an object ejected at a height of 396m.

The energy required for a block ejected at a lower height, travelling 150m, will be more.

For example, at 200m height and 150m ejection:
The time would be around 6.4 seconds.
The velocity would be around 23.4m/s.
E_k = 1/2mv^2 = 453.5 * 23.4^2 = 248KJ.

The 126KJ figure is a best case scenario for an object ejected to 150m.

I'm not sure if any particular pieces of wreckage have been identified with regards to their initial height and their ejection distance. That data would give us better figures to play with.

Originally posted by bsbray11
Once again, no, it isn't. I'm going to stop explaining this, as you obviously aren't paying attention to what I am saying.

Lets see:

Given,

d=150m (TOTAL distance traveled)
t=9s (TOTAL time elapsed)
initial velocity = 0

Now solve this equation!:

d=v0+( (1/2)a(t^2))

Solve this equation for "a."

If you assume that the object accelerates from rest over a period of 9 seconds, its average acceleration is as you say. But the object did not do this. It accelerated from rest in an exceedingly short period of time, and then travelled 150m in 9 seconds decelerating slightly due to air friction.

Yes, as I stated. I am well aware of the fact, I stated it in the very first post on this subject, when you ignored it and assumed I was unaware of this fact. However, YOU are apparently ignorant to the fact that it DOES NOT MATTER when you are calculating the net force, because you have to use the AVERAGE acceleration OF THE WHOLE PERIOD OF TIME IN WHICH YOU ARE ANALYZING.

No, this is absolutely incorrect. You are not working out the 'net force' here, you are making claims about the Kinetic Energy content of the object when it has travelled 150m. By using a formula based on a continuous acceleration, you ignore the fact that the final velocity is marginally smaller than the ejection velocity.

I could not be more clear than that. It sounds to me as if you're begging to join pteridine on my ignore list, but please, solve the equation I posted above for "a". Please please please solve it and tell me what number satisfies it! Then tell me the equation is wrong, or any of the variables I provide are not justified!

They are wrong, the distance travelled is 150m, the time taken is 9s, so therefore the speed is 16.7m/s. To accelerate the object to 16.7m/s, it takes energy 1/2mv^2 or 453.5*16.7^2 or 126KJ.

This is a simple problem, and I understand 'basic physics' well. The assumption that the object continues to accelerate until impact gives it a higher kinetic energy than the true conditions, which were an initial large acceleration followed by 150m travel at a constant speed (ignoring wind resistance).

Originally posted by tezzajw
Bear in mind that this is for an object ejected at a height of 396m.

The energy required for a block ejected at a lower height, travelling 150m, will be more.

This is correct, the height of ejection is determined in the equation by the time taken to reach the ground.

Thanks for confirming my result.

I'm not sure if any particular pieces of wreckage have been identified with regards to their initial height and their ejection distance. That data would give us better figures to play with.

The important number we need to calculate is the mass shedding fraction. bsbray seems happy with a figure of 0.8-0.9, but I would like to see some justification for that, the majority of the debris outside the footprint were exterior columns and various lighter elements. Much of the structure of the building remained within the footprint as the collapse progressed. How much is extremely hard to say.

...and then travelled 150m in 9 seconds decelerating slightly due to air friction....

Are you suggesting that an object falling from somewhere on the building down to the ground will SLOW DOWN due to air friction?

Common sense tells me that objects would ACCELERATE in this situation, I learned that when I was 5, or at least I think I did.

reply to post by P1DrummerBoy


It will reach a terminal velocity based on sectional density. Some may decelarate as they expose different aspects, like the light aluminum panels that covered the columns. Some objects that are lightweight with high surface areas, like paper, may act as airfoils and move upwards.

reply to post by pteridine


Right but aren't they discussing a mass that supposedly weighs ~ 1 ton? I mean unless it had a parachute attached to it..

Originally posted by P1DrummerBoy
Are you suggesting that an object falling from somewhere on the building down to the ground will SLOW DOWN due to air friction?

Common sense tells me that objects would ACCELERATE in this situation, I learned that when I was 5, or at least I think I did.

We're ignoring vertical velocity, taking purely the horizontal component, gravity will not accelerate it, so the only acceleration after ejection is friction from the air.