9/11 Physics from Non-Experts

[beachnut]

Actually, I am interested in truth regardless of who it supports. You didn't address my questions.

So you think explosive in the WTC is real dumb since terrorist flew planes into the WTC without prior knowledge etc? Or What?

You did not address my questions either. Welcome to the forum, it would help to know your overall stand on 9/11, but since you are keeping it secret you must not have any facts to support your ideas or you have no ideas. Since you are an engineer, if you believe in planted explosives I would like some details to include how the charges escaped being cooked off in the random impacts of terrorist planes and random fires. That would be cool if someone had some real stuff to discuss. Like I said it does not matter how much mass was involved, the structure failed. It appears the WTC was strong enough to withstand an impact from a plane that was 7 to 11 times greater then the design impact parameters.

What is the point of your trying to calculate the mass? And what is your single integrated 9/11 story about the WTC towers? You must have some story or why publish in the journal of woo? I say that based on most of the tripe posted at that journal?

It could start like this. I think the WTC was ----, because of --- and ---, and ---.

 

[rwguinn]

GregoryUrich:

I am not an engineer, or a physicist, and my background in such, while at college level, is over a decade old, so I will make no comment on your work, but will follow the discussion.

Welcome to the forum.

TAM

And I will chime in with:
I am an engineer--a structural analyst--and I leave the determination of loading to the people who do that on a professional basis.
When you have determined the loadings, I will look at the results of that loading. That is what I do.
Until then, you guys have fun. I'll tag along and try to offer innane comments and old fogeyisms (just for you, NB-to keep my hand in ) on occasion.

 

[Augustine]

Greg,

I am not sure where PBS or Wikipedia states that 500,000 tons is only the weight above grade of the towers. Bit of a strawman. Second, I would check your claim on Bazant - maybe show your math on how you are extrapolating 480,000 metric tons from his m, and read his paper a little closer. Might I suggest you contact Leslie Robertson as well?

I am assuming that you are still a student with lots of time to burn. While this may be enjoyable to fiddle around with, don't you think Leslie Robertson might just have watched (let alone been involved with) a PBS documentary on the WTC? Don't you think if the weight of the WTC was off by nearly a factor of 2 he might have said something?

Oh well, have fun! I have some other points, but they are relatively minor.

Cheers!

 

[beachnut]

Greg, do you agree with our expert physics student/teacher on his videos? http://www.youtube.com/watch?v=sBfkAzWbnvM

That is one of four of the best Fnet=0 physics yet. What do you think?

 

[GregoryUrich]

Greg,

Here is a hint: there were several water gravity tanks in the WTC which supplied the sprinklers and standpipes. I would suggest doing some back of the envelope calculations. 500,000 tons is not so far off. Might I suggest you contact Leslie Robertson as well? Here is something else to consider: Otis 339HT (12 of those monsters).

I am assuming that you are still a student with lots of time to burn. While this may be enjoyable to fiddle around with, don't you think Leslie Robertson might just have watched (let alone been involved with) a PBS documentary on the WTC? Don't you think if the weight of the WTC was off by nearly a factor of 2 he might have said something?

Oh well, have fun! I have some other points, but I believe once you account for the water storage tanks and the Otis gargantuans, you may not be interested in my minor quibbling over 5 or 10 tons here and there.

Cheers!

I have around 15,000 tons unaccounted for. Thats 500 tons for each of the Otis units which leaves 9,000 tons for water tanks. Anyway, we are talking about less than 5% of the official value (500,000 tons which is 80% higher than my calculated value 279,000 tons).

 

[GregoryUrich]

And I will chime in with:
I am an engineer--a structural analyst--and I leave the determination of loading to the people who do that on a professional basis.
When you have determined the loadings, I will look at the results of that loading. That is what I do.
Until then, you guys have fun. I'll tag along and try to offer innane comments and old fogeyisms (just for you, NB-to keep my hand in ) on occasion.

I have established what I believe are correct loadings. I don't know if you've seen my paper:

...journalof911studies.com/letters/wtc_mass_and_energy.pdf

 

[GregoryUrich]

Greg,

I am not sure where PBS or Wikipedia states that 500,000 tons is only the weight above grade of the towers. Bit of a strawman. Second, I would check your claim on Bazant - maybe show your math on how you are extrapolating 480,000 metric tons from his m, and read his paper a little closer. Might I suggest you contact Leslie Robertson as well?

I am assuming that you are still a student with lots of time to burn. While this may be enjoyable to fiddle around with, don't you think Leslie Robertson might just have watched (let alone been involved with) a PBS documentary on the WTC? Don't you think if the weight of the WTC was off by nearly a factor of 2 he might have said something?

Oh well, have fun! I have some other points, but they are relatively minor.

Cheers!

PBS and Wikipedia state the total mass, not the mass above grade. Interesting that Wikipedia has removed this.

PBS still has it though:

...pbs.org/wgbh/nova/wtc/innovation.html

In the side bar regarding facts.

 

[Furcifer]

Assuming a reduction in mass, does this significantly affect the "impact energy to collapse one floor"? Since the increase or decrease in mass affects the kinetic energy linearly, the ratio should remain the same right? Wouldn't any over or under estimate in the mass be incorporated in this value? Just curious.

 

[rwguinn]

I have established what I believe are correct loadings. I don't know if you've seen my paper:

...journalof911studies.com/letters/wtc_mass_and_energy.pdf

What you believe and the professionals' consensus here are vastly different.
I suggest you perhaps re-think your beliefs and consider carefully the points Professional Engineers and other experts within the field have to say before you continue. The entire analysis has a foundation based on the assumptions made. If those assumptions are invalid, the analysis in invalid.
(I know--believing is never having to say "I think")

 

[GregoryUrich]

The thruth is totally oblivious to what we think or believe.

Unfortunately, there is no professional consensus published. There is no article calculating the mass or potential energy, except mine. Have you read it?

Believe it or not, I change my beliefs based on new or better evidence. I've been working on this for a while. In the beginning it was "I think". Now it is "I believe". Please note I have not said "I know".

 

[rwguinn]

Assuming a reduction in mass, does this significantly affect the "impact energy to collapse one floor"? Since the increase or decrease in mass affects the kinetic energy linearly, the ratio should remain the same right? Wouldn't any over or under estimate in the mass be incorporated in this value? Just curious.

Yes. Any change in mass will affect the KE as a linear function. 1/2 the mass, 1/2 the KE. Fortunately, acceleration due to gravity is independent of mass, as all but the twoofers are aware. The velocity contribution to KE is still important--but all that is post collapse anyway.
The truly important stuff right now is the quasi-static loading (Dead load, plus RMS live load), which is strictly a function of mass and gravity--in other words, weight. And that means that the structural loading absolutely has to be correct.
Unfortunately, Force is a direct linear variation due to mass, also, and stress at failure is a function of force applied. (We won't get too much into the dynamic loading stuff, since that mostly applies after collapse has begun...)

 

[Furcifer]

Yes. This change in mass would only affect the initiation of the collapse, not its progression. This is almost academic then, because we know the collapse started. We only need to be concerned with the floors at or above the impact site.

 

[GregoryUrich]

So you think explosive in the WTC is real dumb since terrorist flew planes into the WTC without prior knowledge etc? Or What?

You did not address my questions either. Welcome to the forum, it would help to know your overall stand on 9/11, but since you are keeping it secret you must not have any facts to support your ideas or you have no ideas. Since you are an engineer, if you believe in planted explosives I would like some details to include how the charges escaped being cooked off in the random impacts of terrorist planes and random fires. That would be cool if someone had some real stuff to discuss. Like I said it does not matter how much mass was involved, the structure failed. It appears the WTC was strong enough to withstand an impact from a plane that was 7 to 11 times greater then the design impact parameters.

What is the point of your trying to calculate the mass? And what is your single integrated 9/11 story about the WTC towers? You must have some story or why publish in the journal of woo? I say that based on most of the tripe posted at that journal?

It could start like this. I think the WTC was ----, because of --- and ---, and ---.

Regarding explosives and whatnot I am an agnostic. I think the eyewitness testimonies, many of them captued live on video from news people, regarding huge explosions prior to collapse are hard to deny. What caused these explosions is another question. My interest in doing these calculations is that the official story is weak and incomplete. I would rather that the enemy of freedom and democracy was a loose gang of terrorists rather than the highly organized and infinitely funded PNAC block, but I suspect the latter.

 

[rwguinn]

Yes. This change in mass would only affect the initiation of the collapse, not its progression. This is almost academic then, because we know the collapse started. We only need to be concerned with the floors at or above the impact site.

Bull's eye!--although I would hedge a bit and add the word "significantly" just ahead of "affect".
Now, if only the twoooferz could get that through their heads...

 

[GregoryUrich]

Yes. This change in mass would only affect the initiation of the collapse, not its progression. This is almost academic then, because we know the collapse started. We only need to be concerned with the floors at or above the impact site.

Actually the change in mass effects the collapse time assuming that the strength of the structure can be calculated from NIST's data. The reduction in PE means there is less energy to spare on elastic and plastic deformation.

How do you guys account for the energy required to pulverize the concrete?

 

[beachnut]

Actually the change in mass effects the collapse time assuming that the strength of the structure can be calculated from NIST's data. The reduction in PE means there is less energy to spare on elastic and plastic deformation.

How do you guys account for the energy required to pulverize the concrete?

Most the dust was wallboard, insulation, spray fire stuff, ceiling tiles. Only truthers fall for the pulverized concrete. Dr Jones himself shows 3 or more floor crushed together, concrete still in big pieces, steel, et al, as a piece of molten metal. What a liar, and he heads up the Journal of 9/11 woo.

If you want to make up stories and join Jim Hoffman in the concrete stuff do so. It is easier to see your true colors.

 

[beachnut]

Regarding explosives and whatnot I am an agnostic. I think the eyewitness testimonies, many of them captued live on video from news people, regarding huge explosions prior to collapse are hard to deny. What caused these explosions is another question. My interest in doing these calculations is that the official story is weak and incomplete. I would rather that the enemy of freedom and democracy was a loose gang of terrorists rather than the highly organized and infinitely funded PNAC block, but I suspect the latter.

There were zero sounds of the explosives used in CD. No one single sound on 9/11 of the cutter charges. Try again. Either you believe in explosives or you do not. It has been 5 years and now some in the truth movement are dubbing in explosives sounds.

99.99 percent of all engineers can see it was a gravity driven collapse. And if you researched properly, you have found the impacts of the aircraft to be 7 to 11 times greater than aircraft impact design. If not you have a lot of catching up to do.

PNAC? Truther by any other name, is still a man of no facts and lacking in evidence. I see PNAC, I see PNAC everywhere.

 

[Furcifer]

Actually the change in mass effects the collapse time assuming that the strength of the structure can be calculated from NIST's data. The reduction in PE means there is less energy to spare on elastic and plastic deformation.

The amount of energy used in elastic and plastic deformation would still be very small in the overall PE/KE equation. As far as the collapse time goes, for the sake of argument i will split the difference and assume a 40% reduction in mass. This only adds about 2 seconds to the overall collapse. This is off the top of my head, i will work the numbers out and get back to you.

 

[GregoryUrich]

There were zero sounds of the explosives used in CD. No one single sound on 9/11 of the cutter charges. Try again. Either you believe in explosives or you do not. It has been 5 years and now some in the truth movement are dubbing in explosives sounds.

99.99 percent of all engineers can see it was a gravity driven collapse. And if you researched properly, you have found the impacts of the aircraft to be 7 to 11 times greater than aircraft impact design. If not you have a lot of catching up to do.

PNAC? Truther by any other name, is still a man of no facts and lacking in evidence. I see PNAC, I see PNAC everywhere.

So you don't want to talk about the live eyewitnesses captured on videotape.

 

[GregoryUrich]

Most the dust was wallboard, insulation, spray fire stuff, ceiling tiles. Only truthers fall for the pulverized concrete. Dr Jones himself shows 3 or more floor crushed together, concrete still in big pieces, steel, et al, as a piece of molten metal. What a liar, and he heads up the Journal of 9/11 woo.

If you want to make up stories and join Jim Hoffman in the concrete stuff do so. It is easier to see your true colors.

Was there no pulverization of concrete? Or was there some pulverization of concrete? How much? Have you seen any photos from gound zero. Everything is buried in essentially sand. These photos outnumber the ones with any substantial pieces of concrete by 100 to 1 based on the 1000s of photos I have seen. Lets see your evidence! Links please.