Science fail x4: supporters of NIST physics still relying on faith, foggy notions, over logic

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jas

Pants-of-dog wrote:

No. That math I did showed that there was conservation of momentum during the collapse. Since Newton's 3rd law is actually based on the law of conservation of momentum, we can safely say that anything that does not violate the law of conservation of momentum also does not violate Newton's 3rd law. Since my math showed that the collapse does not violate the law of conservation of momentum, we can see that Chandler's claim that it violates Newton's 3rd law is simply wrong.

How does Bazant's math not violate conservation of momentum? If you don't moind explaining this to me again. I seem to have missed it the first time around.

Fidel

The score is now: Jas & Isaac Newton 10 Pants-of-dog 0.01 second

jas

Well, gosh, Fidel. Thanks. I think the score has always been about 3-0 for Isaac Newton in this case, but we are having to re-argue these basic, long-accepted principles as if they're under debate here, and having to listen to people who have a little bit of physics knowledge and a little bit of math knowledge try to turn what should be an obvious conclusion into an advanced physics problem. The sole purpose of this is to make the rest of us put our own common sense, ourr own experience of everyday physical events, our common, intelligent, intuitive understanding of how buildings collapse, what that should look like, what gravity can and cannot do, among many other things, into doubt.

NIST and Bazant are hoping we'll be blinded by their "science".

jas

.

Fidel

And with regard to Pants' [url=http://www.rabble.ca/babble/humanities-science/science-fail-nist-physics...$64 thousand dollar question[/url] in the previous thread, we can explain it at least some of the way. A 63.4 metres on-edge concrete floor tilting just one degree makes for a right angle triangle. Using Pythagoras' theorum, the difference in displacement from one end of the floor to the other is 1.11 metre instead of a 3 metre drop for the entire floor area. Garcia's rate of descent of 7.7m/s then changes duration of impact from 0.01s all the way to 0.14 s. And as Griscom noted, the South tower(WTC2) tilted by as much as 23 degrees.

I'm not exactly sure what Griscom's force balance equation might be where he claims force would be reduced from 6.1 times the weight of the upper block to just 1.3 times as mentioned in his Handwaving 9/11 Physics essay. But apparently kinetic energy itself doesn't change. As I said beforem I'm not a physics genie. But what changes in this case is force vector, because in physics, work in joules is not necessarily the same as force in Newtons or N-m. Work is a function of force. A certain amount of energy can be spent applying a large force over a short distance, or a smaller force over a greater distance to achive the same work. Displacement can change, and force can change to do the same amount of work, but the energy to achieve the same work is the same. And, there is no Newtonian law for conservation of force. I'm fairly sure about this.

==

However, Pants and Jas are now discussing column mis-alignment from upper to lower floors. [url=http://forums.randi.org/showthread.php?t=175536&page=10]Here, in a JREF forum,[/url] Tony Szamboti mentions the Balzac-Vitry demolition for which there was lateral displacement of the upper section by several feet. Columns probably did not align from floor to floor. And yet there was significant deceleration according to Szamboti. That is a precedent in building collapse to refer to according to Szamboti.

Pants-of-dog

Fidel wrote:

I wrote:
Even when there are two objects(Bazant's rigid upper block C and massive but vulnerable to 9/11 fairies part A theory), and the two are made of the same materials and the two objects have different mass, the larger object always wins. - Fidel's axiom, which is borrowed from Anders Bjorkman observing Sir Isaac Newton as the original unobserved observer looking on.

Fidel's axiom is an unsupported hypothesis at best. Do you have any evidence to suggest it may be true?

 

Fidel wrote:
So will you or Frank Greening be declaring a quantum theory of 9/11 collapse anytime soon? I declare a Laff-riot! Laughing

Do you know what the difference is between a rigid body and a deforming body?

 

Fidel wrote:
What Szamboti said is that the upper block of the North Tower(WTC 1) actually did not tilt until several seconds into descent. I'm looking at [url=http://www.youtube.com/watch?v=xGAofwkAOlo]Etiene Suaret's video(filmed at 29+ fps)[/url], and I don't see any noticeable tilting until around the 36 second mark. Collapse begins at approx. 32 seconds. There was no significant tilt during collapse initiation of WTC1, therefore more of the kinetic energy should have been distributed through many more support columns of the lower floors than Greening or Bazant suggest was the case.

To be honest, I don't think more than a few columns might have lined up even in a best case scenario. And even if they did, they probably were unable to pass on a significant amount of stress due to not being welded or bolted to each other. You and jas keep talking as if there was a realisitic expectation that the columns would have lined up perfectly and the structure would have behaved as if it hadn't been hit by a jet plane.

 

jas wrote:
Not even analogous. I won't waste my breath.

So, are you then conceding that local asymmetrical damage does not only lead to local asymmetrical collapse?

 

jas wrote:
The calculations you base this conclusion on assume that a layer of rubble is the same as an intact floor.

No, it only assumes that the mass of one demolished flor is equal to the mass on one undemolished floor. This is true because mass does not magically disappear once you dmolish something.

 

jas wrote:
Not only that but that there is a layer of rubble, rather than the powderized concrete we saw exit the collapse waves in massive clouds all the way down.

If you have a reasonable number in terms of the amount of mass that was laterally ejected as powder, as well as a reasonable number in terms of the amount of energy involved in pulveising and ejecting that material, I will be more than happy to add it to the math. The claculations we have done so far show that there was a lot of kinetic energy left over after demolishing each floor. I would be very surprised indeed if these amounts made an appreciable difference.

 

jas wrote:
Not only that but that a layer of rubble will cause no resistance to the descending block of floors. Not only that but that a layer of rubble will somehow adhere to the top floor, increasing its mass, much like a sticky pancake.

It causes no resistance to the upper block because it is falling at the same time and at the same velocity as the upper block. If you want to think of it as adhering to the upper block, you can, but it may not be perfectly correct.

 

jas wrote:
You also haven't shown these calculations that lead you to your simplistic conclusion, and your conclusions don't follow logically. It seems you're hoping that by simply stating something, that we'll think it's true.

I did show how the math proved that the upper block had a higher velocity and kinetic energy after demolishing the first floor. You do not have to take my word for it. All you need to do is check the math.

 

jas wrote:
I asked you where the loss of mass is accounted for in your calculations. You would also need to account for transfer of momentum. I know you don't agree with the latter, but in the real world, i.e., to explain the collapses without any assumption of resistance being removed beforehand, you would need to. But at the very least, with your cartoon-like, two-dimensional model, you need to account for loss of mass at each step.

And as I said, as soon as you provide me with reasonable numbers, we'll look at the math again.

By the way, the equation I used to calculate the velocity of the upper block is the transfer of momentum equation for an inelastic collision:

(m1)(v1)+(m2)(v2)=m(v1+v2)

Momentum is the product of the mass of a moving body and its velocity. In math terms, we would write it like so:

p=mv

where p= momentum

m=mass

and v= velocity.

So, when you make the claim that I don't agree with transfer of momentum, you are simply wrong.

 

jas wrote:
How does Bazant's math not violate conservation of momentum? If you don't moind explaining this to me again. I seem to have missed it the first time around.

Bazant, like me, used the equations of conservation of momentum to figure out the kinetic energy and velocity of the upper block as it collpased the underlying floors.

 

jas wrote:
Well, gosh, Fidel. Thanks. I think the score has always been about 3-0 for Isaac Newton in this case, but we are having to re-argue these basic, long-accepted principles as if they're under debate here, and having to listen to people who have a little bit of physics knowledge and a little bit of math knowledge try to turn what should be an obvious conclusion into an advanced physics problem. The sole purpose of this is to make the rest of us put our own common sense, ourr own experience of everyday physical events, our common, intelligent, intuitive understanding of how buildings collapse, what that should look like, what gravity can and cannot do, among many other things, into doubt.

NIST and Bazant are hoping we'll be blinded by their "science".

I have a very specific question for you, jas. What law of nature or principle of physics have Bazant, Greening or the NIST ignored? I want a specific answer as to the law or principle involved, as well as an explanation as to how they have ignored this law or principle.

Thank you.

 

Fidel wrote:
And with regard to Pants' [url=http://www.rabble.ca/babble/humanities-science/science-fail-nist-physics...$64 thousand dollar question[/url] in the previous thread, we can explain it at least some of the way. A 63.4 metres on-edge concrete floor tilting just one degree makes for a right angle triangle. Using Pythagoras' theorum, the difference in displacement from one end of the floor to the other is 1.11 metre instead of a 3 metre drop for the entire floor area. Garcia's rate of descent of 7.7m/s then changes duration of impact from 0.01s all the way to 0.14 s. And as Griscom noted, the South tower(WTC2) tilted by as much as 23 degrees.

You are apparently confusing the distance between the top of the lower block and the underside of the upper block (3.7m) with the added distance produced when the floor is at angle of one degree (1.11m, assuming the trigonomtery is correct). The first is the space that the upper block falls through, while the second would be the vertical distance that the upper block would have to tear through during impact of the upper block with the lower floor.

Fidel wrote:
I'm not exactly sure what Griscom's force balance equation might be where he claims force would be reduced from 6.1 times the weight of the upper block to just 1.3 times as mentioned in his Handwaving 9/11 Physics essay. But apparently kinetic energy itself doesn't change. As I said beforem I'm not a physics genie. But what changes in this case is force vector...

You don't have to say force vector, as force is by definition always a vector quantity.

Fidel wrote:
, becausein physics, work in joules is not necessarily the same as force in Newtons or N-m. Work is a function of force. A certain amount of energy can be spent applying a large force over a short distance, or a smaller force over a greater distance to achive the same work. Displacement can change, and force can change to do the same amount of work, but the energy to achieve the same work is the same. And, there is no Newtonian law for conservation of force. I'm fairly sure about this.

==

However, Pants and Jas are now discussing column mis-alignment from upper to lower floors. [url=http://forums.randi.org/showthread.php?t=175536&page=10]Here, in a JREF forum,[/url] Tony Szamboti mentions the Balzac-Vitry demolition for which there was lateral displacement of the upper section by several feet. Columns probably did not align from floor to floor. And yet there was significant deceleration according to Szamboti. That is a precedent in building collapse to refer to according to Szamboti.

Szamboti seems to be in the bad habit of making claims without backing up these claims without verifiable numbers.

Fidel

Pants-of-dog wrote:
Do you know what the difference is between a rigid body and a deforming body?

You referred to several exceptions to Newton's third law. I don't understand what quantum theory has to do with what Frank Greening is pushing in regard to collapse theory.

Pants-of-dog wrote:
To be honest, I don't think more than a few columns might have lined up even in a best case scenario. And even if they did, they probably were unable to pass on a significant amount of stress due to not being welded or bolted to each other. You and jas keep talking as if there was a realisitic expectation that the columns would have lined up perfectly and the structure would have behaved as if it hadn't been hit by a jet plane.

I'm not saying columns had to line up perfectly in order that there should have been energy loss. What I'm saying is that Szamboti points to a known demolition where columns of upper and lower sections obviously did not align after a lateral displacement. And there was significant deceleration as per Newtonian mechanics.

Pants-of-dog wrote:
Fidel wrote:
And with regard to Pants' [url=http://www.rabble.ca/babble/humanities-science/science-fail-nist-physics...$64 thousand dollar question[/url] in the previous thread, we can explain it at least some of the way. A 63.4 metres on-edge concrete floor tilting just one degree makes for a right angle triangle. Using Pythagoras' theorum, the difference in displacement from one end of the floor to the other is 1.11 metre instead of a 3 metre drop for the entire floor area. Garcia's rate of descent of 7.7m/s then changes duration of impact from 0.01s all the way to 0.14 s. And as Griscom noted, the South tower(WTC2) tilted by as much as 23 degrees.

You are apparently confusing the distance between the top of the lower block and the underside of the upper block (3.7m) with the added distance produced when the floor is at angle of one degree (1.11m, assuming the trigonomtery is correct). The first is the space that the upper block falls through, while the second would be the vertical distance that the upper block would have to tear through during impact of the upper block with the lower floor.

No I'm referring to a rough beginning time of impact to t=final. I'm even considering that the upper block part C remained rigid throughout, which is baloney because there is no proof that, that was the case. Griscom's example used just one degree of tilt. It's a simple right-angle triangle and reveals an extra 1.11 metre disrance to fall on the high end after initial impact occurs at the lowest end of part C, or whenever part C first makes contact with part A. It's easy peasy.

jas

Pants-of-dog wrote:

jas wrote:
Not even analogous. I won't waste my breath.

So, are you then conceding that local asymmetrical damage does not only lead to local asymmetrical collapse?

[tedious explanation of the stupidly obvious] No, I'm saying there's no comparison between a tripod from which you knock one of its essential supporting legs and a 110-storey concrete and steel highrise which suffered severance of 15% of its columns on two or three top floors.[/tedious explanation of the stupidly obvious]

pants wrote:

jas wrote:
The calculations you base this conclusion on assume that a layer of rubble is the same as an intact floor.

No, it only assumes that the mass of one demolished flor is equal to the mass on one undemolished floor. This is true because mass does not magically disappear once you dmolish something.

Really? How does the crushed material all stay together when the floor is demolished?

pants wrote:

If you have a reasonable number in terms of the amount of mass that was laterally ejected as powder, as well as a reasonable number in terms of the amount of energy involved in pulveising and ejecting that material, I will be more than happy to add it to the math. The claculations we have done so far show that there was a lot of kinetic energy left over after demolishing each floor. I would be very surprised indeed if these amounts made an appreciable difference.

Well, see my above question regarding your assumed cohesiveness of rubble and dust. And it was estimated that the rubble pile at ground zero was about 9 storeys high. I think that's even an overestimate judging from some pictures I've seen. We can add four levels to that for the basement, so 13 levels of crushed matter, from 110 levels. We also know that large amounts of pulverized material was ejected laterally, as is evidenced by the damage to the neighbouring buildings, and the acres of dust several inches thick that settled over lower Manhattan. So, I don't know, 90+ floors not accounted for? But you said that mass doesn't magically disappear, so where did the rest of the building go?

pants wrote:
It causes no resistance to the upper block because it is falling at the same time and at the same velocity as the upper block. If you want to think of it as adhering to the upper block, you can, but it may not be perfectly correct.

The material that gets crushed between teh upper and lower block, according to Pants, "falls" with the upper block onto teh next one. Funny, I know if I were to crush a piece of drywall with my boot against the pavement, the drywall would be crushed against the pavement, adn if I lifted up my boot, I would find it mostly on the pavement, and not under my boot.

In Pants' physical universe it would stick to the bottom of my boot, waiting to be involved in the next crushing mission. And if I were to crush another piece of drywall with the first crushed mound of drywall still stuck to the sole of my boot, it would crush the second piece of drywall, not only more easily, but faster. AND it would also stick to the sole of my boot, rather than the pavement, adding to the mound of crushed drywall under my boot.

pants wrote:
jas wrote:
You also haven't shown these calculations that lead you to your simplistic conclusion, and your conclusions don't follow logically. It seems you're hoping that by simply stating something, that we'll think it's true.

I did show how the math proved that the upper block had a higher velocity and kinetic energy after demolishing the first floor. You do not have to take my word for it. All you need to do is check the math.

You showed calculations that attempt to suggest that. You did not show calculations that then show how velocity increases after that first level, or what happens to the mass at each successive level.

pants wrote:
And as I said, as soon as you provide me with reasonable numbers, we'll look at the math again.

Well, take a look at the visual evidence, and the suggestions I make above. If you're proposing a mathematical calculation that supposedly explains how the collapse was driven, shouldn't it accord with the physical and visual evidence? Why are you asking me? Your  theory needs to accord with the evidence. Or are you saying that the math does not, in fact, attempt to explain the actual collapses?

Finally, your layers of rubble being added to the descending mass make no sense, as you are well aware, or should be.

pants wrote:
jas wrote:
How does Bazant's math not violate conservation of momentum? If you don't moind explaining this to me again. I seem to have missed it the first time around.

Bazant, like me, used the equations of conservation of momentum to figure out the kinetic energy and velocity of the upper block as it collpased the underlying floors.

But the calculations you showed me don't show the upward normal force of the building, i.e., how the stress of the impact would be transferred through the structure, as these large structures are designed to do. Your calculations are only designed to "explain" what was impossible to begin with, not what would be probable. They also don't show how velocity is credibly increased through the crushing of storey after storey of concrete and structural steel. So, no. I'm guessing the answer you provide is incorrect.

pants wrote:
I have a very specific question for you, jas. What law of nature or principle of physics have Bazant, Greening or the NIST ignored? I want a specific answer as to the law or principle involved, as well as an explanation as to how they have ignored this law or principle.

See immediately above, re: the resistance that the building was designed to and would naturally provide, which your calculations don't show.

Thank you.

Fidel wrote:

However, Pants and Jas are now discussing column mis-alignment from upper to lower floors.

I still don't get what the point is regarding this. Column misalignment would suggest to me a speedier arrest of the collapse, as the force pushing downward is now transferred in all kinds of different ways as the columns of the upper block are mostly gone, the rubble is absorbing the impact and deflecting force in all different directions. And the building below the collapse interface is intact, i.e, all columns lined up and working.  Plus I'm pretty sure this is just a Pants-of-dog theory.

Pants-of-dog

Fidel wrote:
You referred to several exceptions to Newton's third law. I don't understand what quantum theory has to do with what Frank Greening is pushing in regard to collapse theory.

Do you know what the difference is between a rigid body and a deforming body?

 

Fidel wrote:
I'm not saying columns had to line up perfectly in order that there should have been energy loss. What I'm saying is that Szamboti points to a known demolition where columns of upper and lower sections obviously did not align after a lateral displacement. And there was significant deceleration as per Newtonian mechanics.

And I responded that Szamboti makes a lot of clams wihout showing any math. How much of a deceleration was there?

 

Fidel wrote:
No I'm referring to a rough beginning time of impact to t=final. I'm even considering that the upper block part C remained rigid throughout, which is baloney because there is no proof that, that was the case. Griscom's example used just one degree of tilt. It's a simple right-angle triangle and reveals an extra 1.11 metre disrance to fall on the high end after initial impact occurs at the lowest end of part C, or whenever part C first makes contact with part A. It's easy peasy.

If the upper block C is rigid, it does not matter what the slope of the lower floor is. Think of a hammer cacking a dinner plate. Does it change the impact time if the plate is on a slope?

 

jas wrote:
[tedious explanation of the stupidly obvious] No, I'm saying there's no comparison between a tripod from which you knock one of its essential supporting legs and a 110-storey concrete and steel highrise which suffered severance of 15% of its columns on two or three top floors.[/tedious explanation of the stupidly obvious]

You forgot to add the part where you explain why my model is not analogous. What is it about the WTC Towers that is so unique that they could only have suffered local asymmetrical damage from local asymmetricl collapse?

 

jas wrote:
Really? How does the crushed material all stay together when the floor is demolished?

It all falls downward at the same velocity.

 

 

jas wrote:
Well, see my above question regarding your assumed cohesiveness of rubble and dust. And it was estimated that the rubble pile at ground zero was about 9 storeys high. I think that's even an overestimate judging from some pictures I've seen. We can add four levels to that for the basement, so 13 levels of crushed matter, from 110 levels. We also know that large amounts of pulverized material was ejected laterally, as is evidenced by the damage to the neighbouring buildings, and the acres of dust several inches thick that settled over lower Manhattan. So, I don't know, 90+ floors not accounted for? But you said that mass doesn't magically disappear, so where did the rest of the building go?

Acres of dust several inches thick? Please provide a source for that.

When you say that 90 floors are not accounted for, are you under the impression that a 110 storey building will turn into a 110 storey pile of rubble? You do realise that the storeys themselves are mostly air, and buildings have interior spaces in them that allow people to use them. Thus, when compacted during demolition or collpase, buildings take up far less volume than they did during use.

 

 

jas wrote:
The material that gets crushed between teh upper and lower block, according to Pants, "falls" with the upper block onto teh next one. Funny, I know if I were to crush a piece of drywall with my boot against the pavement, the drywall would be crushed against the pavement, adn if I lifted up my boot, I would find it mostly on the pavement, and not under my boot.

In Pants' physical universe it would stick to the bottom of my boot, waiting to be involved in the next crushing mission. And if I were to crush another piece of drywall with the first crushed mound of drywall still stuck to the sole of my boot, it would crush the second piece of drywall, not only more easily, but faster. AND it would also stick to the sole of my boot, rather than the pavement, adding to the mound of crushed drywall under my boot.

No, you obvioulsy do not understand. If you stepped on a piece of drywall on the sidewalk, it would not stick to your boot. If you were walking through an old building and your foot went through some rotten floorboards, your boot and the rotten floor boards would both fall through the rotten floor structure with the same acceleration (i.e 9.8 meters per second squared).

 

jas wrote:
You showed calculations that attempt to suggest that. You did not show calculations that then show how velocity increases after that first level, or what happens to the mass at each successive level.

No, I showed calcualtions that definitely showed that. I showed calculations that show how velocity increases after each level. I even pointed out how I used the lightest upper block at the slowest initial velocity (v=0) because if this block had the kinetic energy to collapse the buildings at this relatively slow velocity, then the same block at higher velocities would have had even more kinetic energy to collapse lower floors. This would also hold true for th elarger upper block, which would have also had more KE. In other words, I don't have to show the mass at each level because each floor would have done the same thing (collpased upon impact and added its mass to the falling upper block).

Your inability to understand this even after I explained it to you does not make my math wrong.

 

pants wrote:
Well, take a look at the visual evidence, and the suggestions I make above. If you're proposing a mathematical calculation that supposedly explains how the collapse was driven, shouldn't it accord with the physical and visual evidence? Why are you asking me? Your  theory needs to accord with the evidence. Or are you saying that the math does not, in fact, attempt to explain the actual collapses? 

Any scientific model will leave out certain things in its description of phenomena. This does not mean that it does nto explain actual events. For example, let us look at a pair of reading glasses with green frames. Now, obviously the lenses are not also green, so when someone discusses the green glasses, they are using a descriptor that is only partially correct and does not contain all the information. But it does describe an actual pair of glasses, and this actual pair of glasses will still be accurately descibed as green.

So, my math does decribe the collapses. It does not describe every single solitary thing about the collpases. I am hesitant to believe that such a mathematical explanation, as vast and ponderous as it would be, would be clearly understood here without epic levels of commentary.

I would be more than happy to continue looking at the math, if you wish. Do you have a link or source that discusses clearly how much energy is required to pulverise and eject the dust and other light debris?

 

jas wrote:
Finally, your layers of rubble being added to the descending mass make no sense, as you are well aware, or should be.

You have claimed that. I hope you don't mind if I conclude this part of our discussion by pointing out that I am claiming that the rubble will fall with the upper block because both are falling at the same velocity and acceleration (i.e. gravity), and both started to move at the same time (i.e. impact).

You have yet to explain why this is not so.

 

jas wrote:
But the calculations you showed me don't show the upward normal force of the building, i.e., how the stress of the impact would be transferred through the structure, as these large structures are designed to do. Your calculations are only designed to "explain" what was impossible to begin with, not what would be probable. They also don't show how velocity is credibly increased through the crushing of storey after storey of concrete and structural steel. So, no. I'm guessing the answer you provide is incorrect.

You obviously do not understand physics.

The [url=http://en.wikipedia.org/wiki/Normal_force]normal force[/url] has very little to do with analysing stresses and transfer of loads in structure.

It also is not used in discussions of conservation of momentum, which is what you asked about.

This obvious confusion of terms leads me to believe that you would have trouble with a scientific explanation of how steel structures behave.

Moreover, my math does show how velocity increases as the upper block descends through the lower block. Again, your inability to understand this even after I explained it to you does not make my math wrong.

 

jas wrote:
See immediately above, re: the resistance that the building was designed to and would naturally provide, which your calculations don't show.

The resistance that the building was designed to provide is not a law of nature or principle of physics. The ability of the structure to successfully transfer the load is based on laws of nature and principles of physics, but is not itself one of these. Please try again to answer my question.

By the way, my calculations do show the energy required to demolish a floor in the WTC towers.

Thank you.

 

jas wrote:
I still don't get what the point is regarding this. Column misalignment would suggest to me a speedier arrest of the collapse, as the force pushing downward is now transferred in all kinds of different ways as the columns of the upper block are mostly gone, the rubble is absorbing the impact and deflecting force in all different directions. And the building below the collapse interface is intact, i.e, all columns lined up and working.  Plus I'm pretty sure this is just a Pants-of-dog theory.

I think I might have to draw pictures.

Think of it this way: the only part of the lower block structure that can actually carry the weight of the upper block is the columns. Those are the only parts of the building designed to carry the weight. The windows won't carry that weight. The mechanical ducts won't carry that weight. The toilet partitions won't do it either. The only part that can do it are the columns.

Now what happens when the upper block doesn't land perfectly on the columns?

siamdave

A couple of obvious problems from the above:

1. Post 39, "..mass of one floor and the velocity that this floor would have after dropping from rest (v=0) for a distance of 3.7m..." - a statement that MUST have some proof, as all of the available film, plus common sense, says there is no way the upper sections are dropping unimpeded from 3.7 metres. The tilting section which occupies much discussion here is the most obvious example. And if it is not dropping unimpeded for this distance - as it very obviously is not - then all of the other calculations are meaningless. As is all of the "physics" that desperately tries to explain the obvious controlled demolition without controlled demolition.

2. Post 59 ".. The upper block would, after a while start to tilt northwards, towards the impacted side. It would rotate around a "hinge" made of the columns along the exterior wall of the south elevation... It would then keep tilting northwards until the columns on the south side (that make the hinge) fail completely. At this point, it would stop tilting and fall downwards..."

- a very serious problem here - is the writer aware that the outer columns provided the secondary support for the WTCs 1&2? The main support was the massive matrix of 47 central columns, as in the picture -

consturction of the WTC

 

 

 

 

 

 

 

 

 

 

 

 

- is the writer attempting to imply that all of these massive interior columns were vaporized by the plane impact and explosion, and only the outer columns opposite to the impact side were holding the building up after that?

- looking at this from another angle (no pun intended, really) - is the writer aware that a building has four sides, and in one of the WTC buildings fully three sides were almost entirely intact after the impact, including all four corners, and in the other, only a corner was taken out as the plane very nearly missed the building altogether - but in the one building talked about, in which the building is rotating around the north side after the south side is taken out - what about the east and west sides? At what point have they stopped playing a role here, along with the center columns? This really needs to be explained, first in plain English, and then with the physics to back such speculation up.

 

Pants-of-dog

siamdave wrote:

A couple of obvious problems from the above:

1. Post 39, "..mass of one floor and the velocity that this floor would have after dropping from rest (v=0) for a distance of 3.7m..." - a statement that MUST have some proof, as all of the available film, plus common sense, says there is no way the upper sections are dropping unimpeded from 3.7 metres. The tilting section which occupies much discussion here is the most obvious example. And if it is not dropping unimpeded for this distance - as it very obviously is not - then all of the other calculations are meaningless. As is all of the "physics" that desperately tries to explain the obvious controlled demolition without controlled demolition.

Then what was the distance?

siamdave wrote:
2. Post 59 ".. The upper block would, after a while start to tilt northwards, towards the impacted side. It would rotate around a "hinge" made of the columns along the exterior wall of the south elevation... It would then keep tilting northwards until the columns on the south side (that make the hinge) fail completely. At this point, it would stop tilting and fall downwards..."

- a very serious problem here - is the writer aware that the outer columns provided the secondary support for the WTCs 1&2? ....At what point have they stopped playing a role here, along with the center columns? This really needs to be explained, first in plain English, and then with the physics to back such speculation up.

As I have previously mentioned, the rest of the columns had already been substantially weakened by the flames and by being stressed far past their maximum capacity for approximately one hour.

jas

Pants-of-dog wrote:

Fidel wrote:
You referred to several exceptions to Newton's third law. I don't understand what quantum theory has to do with what Frank Greening is pushing in regard to collapse theory.

Do you know what the difference is between a rigid body and a deforming body?

Not my conversation, but I will be very interested to hear what pants has to say about this relative to the WTC collapses.

pants wrote:
jas wrote:
[tedious explanation of the stupidly obvious] No, I'm saying there's no comparison between a tripod from which you knock one of its essential supporting legs and a 110-storey concrete and steel highrise which suffered severance of 15% of its columns on two or three top floors.[/tedious explanation of the stupidly obvious]

You forgot to add the part where you explain why my model is not analogous. What is it about the WTC Towers that is so unique that they could only have suffered local asymmetrical damage from local asymmetricl collapse?

LOL. Further down, you accuse me of not understanding physics. Pants do you see a difference between an analogy and a comparison?

This is also where you frequently confuse the argument by ascribing an opposite quality to a process than is being claimed. You have done this a few times, and no, I'm not going to search out the posts for you. Here you are asking what is so "unique" about the WTC towers that they should have only suffered asymmetrical collapse from asymmetrical damage (the latter descriptors you also mixed up). In fact, one of the big arguments of the anti-science/denier/believer side is that the Twin Towers were so unique that we can't possibly expect them to respond to localized, asymmetrical damage the way other buildings would. You will find jrootham making this argument.

My argument is not that the towers were so "unique" in terms of structural strength and safety. It's that they were designed very much like other buildings of their time, and would respond, and did respond in the past, very much like other buildings would to minor, local and upper-floor damage. Their height does not affect how they deal with local damage.

pants wrote:
jas wrote:
Really? How does the crushed material all stay together when the floor is demolished?

It all falls downward at the same velocity.

LOL. Did I mention that further down you accuse me of not understanding physics?

pants wrote:

When you say that 90 floors are not accounted for, are you under the impression that a 110 storey building will turn into a 110 storey pile of rubble? You do realise that the storeys themselves are mostly air, and buildings have interior spaces in them that allow people to use them. Thus, when compacted during demolition or collpase, buildings take up far less volume than they did during use.

These buildings didn't compact. They were powderized, as you can see by the numerous photographs and videos.

Quote:
jas wrote:
The material that gets crushed between teh upper and lower block, according to Pants, "falls" with the upper block onto teh next one. Funny, I know if I were to crush a piece of drywall with my boot against the pavement, the drywall would be crushed against the pavement, adn if I lifted up my boot, I would find it mostly on the pavement, and not under my boot.

In Pants' physical universe it would stick to the bottom of my boot, waiting to be involved in the next crushing mission. And if I were to crush another piece of drywall with the first crushed mound of drywall still stuck to the sole of my boot, it would crush the second piece of drywall, not only more easily, but faster. AND it would also stick to the sole of my boot, rather than the pavement, adding to the mound of crushed drywall under my boot.

No, you obvioulsy do not understand. If you stepped on a piece of drywall on the sidewalk, it would not stick to your boot. If you were walking through an old building and your foot went through some rotten floorboards, your boot and the rotten floor boards would both fall through the rotten floor structure with the same acceleration (i.e 9.8 meters per second squared).

Pants, the progressive collapse theory requires crushing of floors, not falling. You can't "fall" through 240 perimeter columns and 40 massive core columns. When your alleged upper block of floors crushes through a floor, it is creating the rubble. Further, in order for the upperblock to meet each successive floor of the lower block, it must displace much of the rubble it is creating, kind of like if you build a sandwich too high, the contents start falling out. Much of this rubble is being displaced, as we can also see in the pictures.

I think you need to decide what exactly the process is you're describing.

pants wrote:

No, I showed calcualtions that definitely showed that. I showed calculations that show how velocity increases after each level.

hypothetically.

A mathematical model is hypothetical, pants.

pants wrote:
I even pointed out how I used the lightest upper block at the slowest initial velocity (v=0) because if this block had the kinetic energy to collapse the buildings at this relatively slow velocity, then the same block at higher velocities would have had even more kinetic energy to collapse lower floors. This would also hold true for th elarger upper block, which would have also had more KE. In other words, I don't have to show the mass at each level because each floor would have done the same thing (collpased upon impact and added its mass to the falling upper block).

Bolding to highlight the cartoon premise of your logic.

Did I mention you accuse me of not understanding physics?

Fidel

Pants-of-dog wrote:
Do you know what the difference is between a rigid body and a deforming body?
Fidel wrote:
I'm not saying columns had to line up perfectly in order that there should have been energy loss. What I'm saying is that Szamboti points to a known demolition where columns of upper and lower sections obviously did not align after a lateral displacement. And there was significant deceleration as per Newtonian mechanics.

And I responded that Szamboti makes a lot of clams wihout showing any math. How much of a deceleration was there?

[url=http://the911forum.freeforums.org/demolitions-using-a-falling-upper-bloc... says here,[/url] a 20% reduction in velocity. It's a demonstration of Newton's third law.

[url=http://www.youtube.com/watch?v=syzKBBB_THE]démolition de la tour ABC Balzac à Vitry-sur-Seine[/url] (YouTube video)

1. The roofline of ABC building shows deceleration after an 11 metre free-fall and indicating that the lower structure is providing resistance
2. The upper block is destroyed just like the lower block, demonstrating Newton's third law
3. There are no explosives used, so there are no jolts or "bangs" (Popular Mechanics, NIST)

Pants-of-dog wrote:
Fidel wrote:

No I'm referring to a rough beginning time of impact to t=final. I'm even considering that the upper block part C remained rigid throughout, which is baloney because there is no proof that, that was the case. Griscom's example used just one degree of tilt. It's a simple right-angle triangle and reveals an extra 1.11 metre disrance to fall on the high end after initial impact occurs at the lowest end of part C, or whenever part C first makes contact with part A. It's easy peasy.

If the upper block C is rigid, it does not matter what the slope of the lower floor is. Think of a hammer cacking a dinner plate. Does it change the impact time if the plate is on a slope?

1. Where's your proof that part C remained rigid? You have none, and neither does Bazant or Greening.

2. Now think of a hammer that is 64 metres in diameter across the face and cracking a big concrete dinner plate just as long. Now tilt the hammer face just one degree from horizontal. Now imagine dt increasing from 0.01 s all the way to 0.14. [url=http://www.cleavebooks.co.uk/scol/calrtri.htm]right angle triangle calculator[/url]

Also, remember that Bazant claims there was nil next to no loss of mass as the "rigid upper block" descended. This FEMA debris map shows how absurd Bazant's claim is.

[IMG]http://img.photobucket.com/albums/v697/rabblerabble/fig3.jpg[/IMG]

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Closing for length.

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