Momentum Transfer in WTC

[rwguinn]

I'll wait. Please, anyone, link us to photo or video evidence of macroscopic anything (besides metal) at ground zero. It appears that there was very very little.

murray suggested we

a) the cinder block would shatter, but not powderize.
b) this is not particularly relevant, because the twin towers turned to powder in mid air, not when stuff hit the ground. Please review the evidence.

Now, where is that Don Quixote smiley????

 

[apathoid]

steve s asked

Well, according to NIST logic, not very much. According to them, all that would be needed is enough explosive to break the vertical supports on one floor, and gravity would do the rest.

I (and Gordon Ross) happen to think that is absurd. But if you agree with NIST's findings, then this it follows logically.

This is completely my point. YOU think its absurd, so I'd like to know how much C4 is required to micronize 99% of the concrete, if a collapse couldnt account for it. I think there is an explosives expert here at JREF(Huntsman?) who may be able to set you straight with some staggering numbers...

(But why in the hell would they wire the floors as opposed to the columns)

 

[TruthSeeker1234]

gravy admonished

you'll learn that arguing from incredulity ("It couldn't happen because I don't believe it could happen") is dealt with swiftly and savagely by the JREF ninjas here.

We could just as easily say that the OCT's are arguing from incredulity: It couldn't have been a controlled demolition because I can't believe "my" government would do such a thing, I can't believe so many people would keep the secret, etc.

RIght?

C'mon, focus on the science, most of this thread is going well.

 

[Gravy]

gravy admonished

We could just as easily say that the OCT's are arguing from incredulity: It couldn't have been a controlled demolition because I can't believe "my" government would do such a thing, I can't believe so many people would keep the secret, etc.

RIght?

C'mon, focus on the science, most of this thread is going well.

Dead wrong. We require evidence. You have provided none.

"Focus on the science?" How about answering this question, which I ask for the third time: what is your source for your contention that at least half of the towers were reduced to particles of 100 microns (1/10th mm, which is much smaller than the period at the end of this post) or less?

Cut the crap and give us your answer.

 

[rwguinn]

gravy admonished

We could just as easily say that the OCT's are arguing from incredulity: It couldn't have been a controlled demolition because I can't believe "my" government would do such a thing, I can't believe so many people would keep the secret, etc.

RIght?

C'mon, focus on the science, most of this thread is going well.

Ok--We will.
Where is your source for the "100 micron" particles? We can't do the math without the data.

 

[Kent1]

Dead wrong. We require evidence. You have provided none.

"Focus on the science?" How about answering this question, which I ask for the third time: what is your source for your contention that at least half of the towers were reduced to particles of 100 microns (1/10th mm, which is much smaller than the period at the end of this post) or less?

Cut the crap and give us your answer.

A lot of this "100..60...etc. Micron talk" was caused by Hoffman's poor research.

http://www.911myths.com/html/particle_size.html

 

[TruthSeeker1234]

Please refrain from vulgarity, gravy. I will excuse it one time, after that I will ignore you. I will continue to answer the question, as I already have.
My evidence that some very large percentage of the non-metallic contents of the twin towers was converted to powder is as follows:

THe entire body of photographic and video evidence.

Perhaps this one will serve as a nice point of discussion.

http://911research.wtc7.net/papers/dustvolume/docs/wtc1_dust_2en.jpg

Where once there was a tower, there now is a mushroom cloud. Meanwhile, there are voluminous clouds of concrete powder billowing in every direction. When the dust settles, it settles from river to river, inches deep. There is almost no macroscopic chunks of non-metallic stuff at ground zero, based on the photos and videos.

If someone will send pictures that refute this I will stand corrected. So far we have one picture showing about one ton of material, allegedly from ground zero. We need to account fo about 99,999 tons more. Let's keep trying.

 

[TruthSeeker1234]

Scott! Nice to see you!

 

[Arkan_Wolfshade]

...
This is not particularly relevant to the present discussion. Observe any of the photos and videos of the twin towers. Huge amounts of very dense dust along with chunks of steel and aluminum is being projected sideways, even upwards, and is obviously does not "ricochet" off of anything.

Mackey, where is your evidence that concrete ricocheted?
...

RE: Ejection of Materials:

In order to allow time for lateral motion, the exterior column(s) that hit WFC 3 were most probably from the upper half of WTC 1. A fall from 1,000 feet to 240 feet would take SQR(2*h/g) = around 6.9 seconds where h = 760 feet and g = 32.17 ft/s^2. In the horizontal plane, a uniform acceleration of 20 m/s^2 for the first second followed by negligible deceleration due to drag for the remaining 5.9 seconds would provide 10 + (5.9 * 20) = 128 metres = 420 feet displacement. At 1,000 feet the WTC 1 perimeter columns, per story, were comprised of:

two flanges of 1/2 x 13.5 x 144 inches each, totalling 1,944 ins^3
one outer web of 1/4 x 13 x 144 inches = 468 ins^3
one inner web of 1/4 x 15.75 x 92 inches = 362 ins^3
one spandrel plate of 3/8 x 40 x 52 inches = 780 ins^3

...totalling 3,554 ins^3 per floor or 10,662 ins^3 = 6.17 ft^3 for a three-floor section which at 490 lb/ft^3 is 3,023 lb (84 pounds per lineal foot) or 1,371 kg. (There is some uncertainty as to the flange thickness; it was known to be only 1/4" at the very highest floors.) The force require to produce an acceleration of 20 m/s^2 in an inertia mass of 1,371 kg is 20 * 1371 = 27,420 N = 6,165 lbf.

The cross-section presented to a wind, per floor, would be 40 x 52 = 2,080 ins^2 for the spandrel plate and 15.75 x 92 = 1,449 ins^2 for the inner web, totalling 3,529 ins^2 per floor or 10,587 ins^2 = 6.83 m^2 for a three-story section of exterior column. (So the required pressure is well under 1 psi.) From the drag equation of

d = Cd * A * r * 0.5 * v^2

we obtain

v = SQR(2 * d / (Cd * A * r))

where r = density of air ~ 1.2 kg/m^3 and assuming a relatively high drag coefficient Cd of 4 / pi ~ 1.27 for a flat plate and d = the previously calculated force of 27,420 N and A = 6.83 m^2 as calculated above. This places the required wind at 72.6 m/s = 162 mph for one second duration. Actual windspeed on the day was up to 10 mph on the ground and up to 20 mph at higher altitude.

Suppose we imagine the collapse initiating at 1,200 feet, and proceeding as per the "pancaking" theory to 1,000 feet. After freely falling 200 feet, the terminal velocity would be SQR(2 * 200 * 32.17 ft/s^2) = 113.4 fps = 77.3 mph. In this theory, there is a small delay due to resistance of the intact building below, but the falling upper section smashes its way through each floor in about 0.1 seconds at the 1,000 feet level. The volume of air per floor is approximately 12 * 200 * 200 feet = 480,000 ft^3. Some will go down, but if the total was forced out through a perimeter of 800 feet by an average height of 6 feet which is an exiting area of 4,800 ft^2, it would (continuing outward) extend for some 100 feet at the end of the 0.1 seconds which is a velocity of 1,000 fps or 682 mph.

Let's set the exiting gases velocity at just 700 fps = 213 m/s, in which case the force acting on the exterior column for 0.1 seconds is given by:

d = Cd * A * r * 0.5 * v^2

= 1.27 * 6.83 * 1.2 * 0.5 * 213^2 ~ 236,000 N

to produce an acceleration of F / m = 236,000 N / 1,371 kg = 172 m/s^2. After 0.1 seconds the velocity of the steel is 17.2 m/s = 38.5 mph, and the horizontal displacement is 0.86 metres. Following another 6.8 seconds at 17.2 m/s the total distance travelled horizontally is 0.86 plus 6.8 * 17.2 ~ 118 metres = 387 feet. The columns have to shear off quickly enough, and the pancaking theory has the problem that the gravitational potential appears to be too low for all the energy sinks, but even this scenario does not appear to rule out the idea that debris could end up a few hundred feet away.

source

Energy released:

Large quantities of energy were stored in the buildings during their construction. For example, the construction of WTC 1 resulted in the storage of more than 3 x 1012 J of potential energy over the 1,360 ft height of the structure. Of this, approximately 7 x 1010 J of potential energy was stored in the upper part of the structure—above the impact floors—relative to the lowest point of impact. Once collapse was initiated, this energy was rapidly released and converted into kinetic energy—in the form of the rapidly accelerating mass of the top part of the structure. The impact of this rapidly moving mass onto the lower structure caused a wide range of structural failures in the floors directly at and below the aircraft impact zone, in turn causing failure of these floors. As additional floor plates failed, the mass associated with each of these floors joined that of the tower above the impact area, unleashing further destructive energy on the floors immediately below. This initiated a chain of progressive failure until total collapse of the building ensued.

source

 

[TruthSeeker1234]

Arkan, showing calcs of how much energy and time is required when something happens is not the same as showing that it did happen. Please, can anyone show me a video of stuff that ricochets? I observe a systematic horizontal outflow of very dense dust that starts coming out of all four sides of the tower from the very beginning all the way until the end of the collapse.

 

[Arkan_Wolfshade]

Arkan, showing calcs of how much energy and time is required when something happens is not the same as showing that it did happen. Please, can anyone show me a video of stuff that ricochets? I observe a systematic horizontal outflow of very dense dust that starts coming out of all four sides of the tower from the very beginning all the way until the end of the collapse.

WTF are you talking about?

 

[Loss Leader]

Where once there was a tower, there now is a mushroom cloud. Meanwhile, there are voluminous clouds of concrete powder billowing in every direction. When the dust settles, it settles from river to river, inches deep. There is almost no macroscopic chunks of non-metallic stuff at ground zero, based on the photos and videos.

Truthseeker, what in the [rule8]ing [rule8] is your contention? Are you contending that a controlled demolition of the bottom supports of the towers would pulverize the buildings but that tower failure from the 83rd floor down would not? If your theory of a controlled demolition doesn't account for the 50% pulverization that you claim, then I'm not sure what ground you have to question any other theory. How do you contend the towers were brought down and how does your contention create the type of debris you claim?

I'm betting you don't answer that.

In the meanwhile, here's a picture of all sorts of debris from the WTC. I saved it on my computer and blew it up. I saw a chair. Look at it all night, if you like. Play Where's Waldo. Then answer my question.

 

[Gravy]

Please refrain from vulgarity, gravy. I will excuse it one time, after that I will ignore you. I will continue to answer the question, as I already have.
My evidence that some very large percentage of the non-metallic contents of the twin towers was converted to powder is as follows:

THe entire body of photographic and video evidence.

You know what's vulgar, "TruthSeeker?" Your insistence that we stick to the science while refusing to back your claims with any. What is your problem? Final time: what, in the "entire body of photographic and video evidence," shows that at least half the towers were reduced to 100 microns or less?

You made a specific claim. Prove it or admit that you have no proof.

 

[Brainache]

Arkan, showing calcs of how much energy and time is required when something happens is not the same as showing that it did happen. Please, can anyone show me a video of stuff that ricochets? I observe a systematic horizontal outflow of very dense dust that starts coming out of all four sides of the tower from the very beginning all the way until the end of the collapse.

I don't have any videos, but I think a fair bit of crushed drywall and ceiling tiles would have been blown out by all the air that was being forced out by the floors compacting on their way to the ground.

There are lots of posts in other threads showing pics of debris much bigger than the 100microns you talk about.

I've seen pictures of conveyor belts with people picking through chunks of the stuff looking for flight recorders etc.

But as it seems you have already made your conclusions without real evidence, I can't see much point in anyone providing you with it.
If you checked the links already posted by others in this thread you will have seen real evidence.

Anyway welcome to the forum where no one is banned for disagreeing.(unlike others I could name)

 

[Kent1]

Scott! Nice to see you!

Thanks, nice to see you bringing up the same points. LOL!
http://www.atfreeforum.com/911studi...s=0&postorder=asc&start=135&mforum=911studies

 

[Arkan_Wolfshade]

I don't have any videos, but I think a fair bit of crushed drywall and ceiling tiles would have been blown out by all the air that was being forced out by the floors compacting on their way to the ground.

There are lots of posts in other threads showing pics of debris much bigger than the 100microns you talk about.

I've seen pictures of conveyor belts with people picking through chunks of the stuff looking for flight recorders etc.

But as it seems you have already made your conclusions without real evidence, I can't see much point in anyone providing you with it.
If you checked the links already posted by others in this thread you will have seen real evidence.

Anyway welcome to the forum where no one is banned for disagreeing.(unlike others I could name)

This whole pictures/video line of reasoning is flawed for so many reasons anyway. Aside from that, we've already seen one pic provided, but apparently that is not enough. Which gives me the distinct impression that this will turn into another "god of the gaps"/transitional-fossil type argument. How many pics of debris need to be provided? etc?

You (Truthseeker) brought up Dr. Greening's article. If you take issue with some part/all of it then please, bring up the specific point and let's discuss that specific point.

 

[David Wong]

I guess I don't understand. Is vast pulverization the sign of a controlled demolition? It isn't, is it?

So why do they focus on this? I've read a lot about 9/11 conspiracy theoris but I can't keep up with all of them.

 

[Kent1]

I guess I don't understand. Is vast pulverization the sign of a controlled demolition? It isn't, is it?

So why do they focus on this? I've read a lot about 9/11 conspiracy theoris but I can't keep up with all of them.

Some believe there was some sort of mini nuke. Others believe all of the concrete was wired methodically with explosives. Some believe that the building was built with explosives inside.
Basicly they KNOW concrete should not have behaved as it did on 9/11.

 

[Foolmewunz]

I'll wait. Please, anyone, link us to photo or video evidence of macroscopic anything (besides metal) at ground zero. It appears that there was very very little.


a) the cinder block would shatter, but not powderize.
b) this is not particularly relevant, because the twin towers turned to powder in mid air, not when stuff hit the ground. Please review the evidence.

Powderize? No wonder Mackey left for parts unknown. You can't have a scientific discussion with someone who knows about powderization without doing some massive research. And they powderized in mid-air? Are you citing physics from Planet X? This sounds like gravimation theory from the ol' Kingfish. It done powderized!

And just what is "macroscopic"? I know what it means. Do you? Are you saying that in the thousands of pictures available all you see is dust? There are enough pictures of debris OF ALL SIZES SHAPES AND COLORS on the ChristopherA thread that one tends to believe you just woke up last week and got an email from a guy who knew a guy who's sister heard this broadcast. The word of Pataki versus thousands of photos? Hmm? I'll stay with the out of context quotes!

Even if you won't accept the photographic evidence (somehow I doubt you will), then maybe you want to go talk to these guys......

http://www.nysm.nysed.gov/exhibits/longterm/documents/recovery.pdf#search="Debris at WTC"

I think they may have a certain amount of material at "macroscopic" sizes for you. They spent months sorting the stuff, after all! Or are you going to posit that this was false debris, trucked in from some other major catastrophe that we never heard about?

Here's some mainstream press for you.
http://www.time.com/time/photoessays/groundzero/1.html

I see pieces of debris larger than human beings in these pictures. Is that sufficient to move past this dumb request?

Now, as Loss Leader asked, can we get on with your underlying contention here? Just what is your particular theory? No planes? UFO's? CD? NWO? Illuminati? Global Zionist Conspiracy? Take a break. Go get a cuppa coffee. We'll still be here when you've decided to tell us what it is you're getting to. So far, you're just a troll, though.

 

[kevin]

Where are the pictures of 100 micron powder? Where are the pictures of explosives in the floors and walls?

Until you can provide these you have no proof.