The Demolition of the World Trade Center Towers.

[reprehensor]

From the PhysOrg.com Forum.

Dear All,

I invite everyone reading this to disprove basic Physics and Chemistry I (and many others) have presented regarding the collapse of the World Trade Centre towers.

Please look at this:

Flash slideshow.

Then consider if NIST is/are correct http://www.physorg.com/news3686.html

<[ Due to website access problems, I have mirrored this file here>]:

Flash mirror 1
Flash mirror 2

People can disagree with me for sure, but please point out the error in my Physics if you are going to do so.

Thanks for reading.

Incidentally, this thread has gained some notoriety because an apologist for the 'official story' outs himself as an employee of the PR department of the ASCE after some heated exchanges;

I work at the American society of civil engineer, an office which contributed massively at the NIST report. I work at the public relation department, so if I seem angry when I post, its because my *** is on the line; they want to shut down our department because of people like you who oppose the official version. Politicians don't want another scandal.

The question is, was he on the clock? Is this what a 'PR' person for the ASCE does between coffee breaks?

If he's got all this time on his hands, perhaps he could whip something up to explain this;

NIST told NCE this week that it did not believe there is much value in
visualising quasi-static processes such as thermal response and load
redistribution up to the point of global collapse initiation and has chosen not
to develop such visualisations.

(From the article blogged here.)

[Make7]

1. My favorite part is....

... the "slide" pointing out that the BBC graphic is factually incorrect. Although it is true that the graphic is almost completely wrong, I find it ironic that someone who makes so many factual errors would point this out in the manner they did.

Examples of errors in the slide show (before pointing of the BBC's error):

• "Steel beams melted..."
  
• "The Towers were 1350 feet tall."[s]
  
• "One tower collapsed in about 10 seconds."
  
• "The 2^nd tower collapsed in about 8.1 seconds."

Good stuff.

-Make7

[dailykoff]

2. It's not bad.

You're probably sneering but the information is perfectly accurate. There are several ways to measure building height, to top of roof and to top floor for example, and 1350' measures the latter. I understood "steel beams melted" as an example of an official claim. I don't understand your beef with the collapse times or why it would make the least difference. And some people still take the BBC graphic seriously (present company excepted, of course).

The only bone I'd pick is that they compare concrete buildings (the collapse photos) to steel buildings without identifying the difference or pointing out that steel buildings do not, repeat not collapse except through the use of explosives.

(There's one known case of a short steel building partially collapsing in a Mexican earthquake, but I saw a photo of it and it looked to me like it had a concrete frame.)

[Make7]

3. perfectly accurate?

dailykoff wrote:

There are several ways to measure building height, to top of roof and to top floor for example, and 1350' measures the latter.

I assume that you realize the reasons there are different measures of building height. Which one do you feel should be used for calculating the collapse time of a building?

dailykoff wrote:

I don't understand your beef with the collapse times or why it would make the least difference.

The slideshow uses the collapse times as part of its case. Whoever produced it thought it makes a difference. I'm just saying it would be advisable to use accurate collapse times if you are building a case upon that as evidence.

dailykoff wrote:

The only bone I'd pick is that they compare concrete buildings (the collapse photos) to steel buildings without identifying the difference or pointing out that steel buildings do not, repeat not collapse except through the use of explosives.

Except, of course, when they collapse in an earthquake. Or fire.

-Make7

[dailykoff]

4. Perfectly.

That's very nice HTML, but I don't see any information refuting any of my points.

[Make7]

5. How many explosives did this take?

dailykoff wrote:

...steel buildings do not, repeat not collapse except through the use of explosives.

Total collapse of 21-story steel frame office building. Note building standing in background. Many tall concrete structures whose designs met the requirements of the building code performed well. When the magnitude and duration of the quake are considered, the performance as a whole of the one million structures in the city was very good. Photo credit: E.V. Leyendecker, National Bureau of Standards

?pic">Thumbnail image
Download full resolution TIF image

http://www.ngdc.noaa.gov/seg/hazard/slideset/3/3_slides.shtml

-Make7

[dailykoff]

6. Yes, that's the building I mentioned.

The short structure in Mexico (21 floors) that looks like it had a concrete frame. Look carefully at the lower levels.

In any case, notice that the collapse is not in fact "total," and that the bulk of the structure appears to have rotated off its base and fallen 90 degrees, more or less intact, like a tree.

The conservation of angular momentum tells us that rigid structures that begin such rotations--like the top sections of the Trade Center towers--will do exactly that, not disintegrate in midair like fireworks.

[Make7]

11. How are you defining "partial" collapse?

Other people seem to describe it as total:

• before V0.64: the page Collapsing Buildings stated: prior to September 11th, no steel framed building had ever undergone total collapse due to any cause or combination of causes other than controlled demolition. Also the page Collapsing Skyscrapers stated: .. no steel framed high-rise in history had ever collapsed of its own weight due to any cause or combination of causes -- be they bombings, severe fires, earthquakes, or hurricanes. Subsequent research turned up the case of a 21-story steel frame office building that "totally collapsed" because of the 8.1 magnitude 1985 Mexico City earthquake. Since a 21-story building qualifies as a high-rise but not a skyscraper, high-rise was changed to skyscraper in the second passage.
  
  
  Source: http://www.911research.wtc7.net/re911/corrections.html

What source, if any, are using for the criteria of "partial" vs. "total" collapse?

-Make7

[dailykoff]

13. Glad you asked.

The question is answered in the next sentence of the source you cited:

"However, the photograph shows that the remnants of this 21-story building included several apparently intact stories. This contrasts with the pulverized remains of the 110- and 47-story skyscrapers of the World Trade Center."

[Make7]

14. apparently intact

Here is a photograph of that 21-story office building:



What are the numbers of the floors you believe are "apparently intact"?

-Make7

[dailykoff]

16. Hard to say from this photo.

But if you're really interested, why don't you send a query to the person who wrote it, whose website you cite as your authority?

[Make7]

17. On what then are you basing your claim?

dailykoff wrote:

(There's one known case of a short steel building partially collapsing in a Mexican earthquake, but I saw a photo of it and it looked to me like it had a concrete frame.)

Post#2

Do you have different photo of that building that shows what you claim is in fact true?

Are you basing your "partial collapse" assessment entirely on one quote that says "the remnants of this 21-story building included several apparently intact stories"?

-Make7

[dailykoff]

18. The available evidence.

On the basis of this photograph, which is not very good, I'd say that at least one floor above ground remains standing, and that it has a concrete frame.

That's not a "claim" that anything "is in fact true"; it's a description of what I see.

[Make7]

19. One picture is the available evidence?

The organization that compiled the book entitled Behavior of Steel Structures in Seismic Areas had this to say about that building failure:

"Although steel structures generally performed well during the past earthquakes, severe damages were observed in the steel frames of the Morisada building in Sendai, Japan after the 1978 Miyagi-Oki earthquake (Wang and Lu, 1984). Total collapse of the 21 story Pino Suarez tower occurred during the 1985 Mexico City earthquake (Ger, Gheng and Lu, 1993). This building used a combination of concentrically braced frames and moment-resisting frames. The causes of these damages are now well understood. With continuing research on the various issues discussed, it is certain that improved seismic analysis and design methodologies for steel structures will evolve. These methodologies will help insure that severe damage or collapse will not occur in the future."

I think that instead of relying on your description of "the available evidence", I will rely on the observations of people who have actually researched this incident.

-Make7

[dailykoff]

20. I don't see any other pictures

or documentation of this source, so yes, my description is based on the available evidence.

You may also be interested to know that in my judgement there are no useful parallels to be drawn between the structure or behavior of this building and the Trade Center buildings, period.

[Make7]

23. Perhaps you would find some if you bothered to look.

?pic
?pic

The book is available for purchase from www.amazon.com. You can also search the contents of the book on their site. Use the search term "Pino Suarez".

The quote I previously posted appears on page 51. More complete information for the reference they cited in that paragraph can be found on page 52:

Ger, J. F., Cheng, F. Y. and Lu, L.W., (1993) Collapse behavior of Pino Suarez building during 1985 Mexico City earthquake. Journal of Structural Engineering, ASCE, Vol. 119, No. 3, pp. 852-870.

If you do not have an www.amazon.com account, you can also search the contents on books.google.com.

No useful parallels?

dailykoff wrote:

Yes, that's the building I mentioned.

The short structure in Mexico (21 floors) that looks like it had a concrete frame. Look carefully at the lower levels.

In any case, notice that the collapse is not in fact "total," and that the bulk of the structure appears to have rotated off its base and fallen 90 degrees, more or less intact, like a tree.

The conservation of angular momentum tells us that rigid structures that begin such rotations--like the top sections of the Trade Center towers--will do exactly that, not disintegrate in midair like fireworks.

Post#6

No useful parallels.

Okay...if you say so, but why exactly did you bring it up then?

I doubt if you are interested, but I still believe I should rely on the research of professionals concerning this building collapse.

-Make7

[dailykoff]

27. No need, as there are no useful parallels. n/t

[Make7]

30. So then you brought it up for no reason?

That can't be right.

You brought it up, presumably to support your claim "that steel buildings do not, repeat not collapse except through the use of explosives." (Post#2) However, since professionals that actually researched the Pino Suarez collapse determined that it totally collapsed in the 1985 earthquake, it would seem that your assertion that steel buildings only collapse from explosives is incorrect.

Your basis for determining that the building was a "partial" collapse is based on an extremely small sample of the available evidence and appears to be little more than your questionable interpretation of a single photograph. Perhaps we should look at the abstract of the previously mentioned article in the Journal of Structural Engineering (Post#23):

Extensive inelastic analyses have been performed for the building by using the multicomponent seismic input of actual Mexico City earthquake records. It was found that the structural response exceeds the original design ductility of this building, and most girders in the building have severe inelastic deformation. Due to the load redistribution that results from ductile girder failure, local buckling occurred in many columns on floors 2, 3, and 4. Therefore, most columns on floors 2–4 lost their load-carrying capabilities and rigidities, which then caused the building to tilt and rotate. It is evident that ductile failures of girders combined with local buckling of columns in the lower part of the building resulted in significant story drift, building tilt, P- effect, and the failure mechanism.

You posted a quote saying that the "building included several apparently intact stories. This contrasts with the pulverized remains of the 110- and 47-story skyscrapers of the World Trade Center." (Post#13) None of the available evidence indicates there were several intact stories. I am still wondering how you are able to conclude that this building only "partially" collapsed. If any part of the structure remains standing, do you consider it a partial collapse?

-Make7

[dailykoff]

33. Notice the use of parentheses.

Now look up "parenthetical" in your dictionary, and you'll have your answer.

No need to thank me. :)

[Make7]

36. Okay, I won't thank you.

Main Entry: pa·ren·the·sis
Pronunciation: p&-'ren(t)-th&-s&s
Function: noun
Inflected Form(s): plural pa·ren·the·ses /-"sEz/
Etymology: Late Latin, from Greek, literally, act of inserting, from parentithenai to insert, from para- + en- en- + tithenai to place -- more at DO
1 a : an amplifying or explanatory word, phrase, or sentence inserted in a passage from which it is usually set off by punctuation b : a remark or passage that departs from the theme of a discourse : DIGRESSION
2 : INTERLUDE, INTERVAL
3 : one or both of the curved marks ( ) used in writing and printing to enclose a parenthetical expression or to group a symbolic unit in a logical or mathematical expression
- par·en·thet·i·cal /"par-&n-'the-ti-k&l/ also
par·en·thet·ic /-tik/ adjective
- par·en·thet·i·cal·ly /-ti-k(&-)lE/ adverb

http://www.m-w.com/dictionary/parenthetical

If I had to choose, I'd go with 1a. Is that the one you meant?

So do you feel that it's okay to make factually inaccurate statements as long as you support them with information enclosed in parentheses that is also not true?

-Make7

[dailykoff]

39. And I won't answer your rhetorical question,

so I think we're done.

[Make7]

41. I'll take that as a YES. ( n/t )

[dailykoff]

43. YES, my original statements are accurate,

YES, the Pino Suarez building is a digression, and
YES, if you want to repeat this discussion, you'll have to do it without me.

[Make7]

47. Perhaps this may be of some help:

accurate

Function: adjective
Etymology: Latin accuratus, from past participle of accurare to take care of, from ad- + cura care
1 : free from error especially as the result of care <an accurate diagnosis>
2 : conforming exactly to truth or to a standard : EXACT <providing accurate color>
3 : able to give an accurate result <an accurate gauge>
synonym see CORRECT

http://www.m-w.com/dictionary/accurate

Now let's look at your original statements that we have been discussing:

dailykoff wrote:
...steel buildings do not, repeat not collapse except through the use of explosives.

Post#2

The Pino Suarez building collapse is a case of a steel building that collapsed without the use of explosives, therefore your statement is inaccurate.

dailykoff wrote:
There's one known case of a short steel building partially collapsing in a Mexican earthquake...

Post#2

Engineers that have studied the Pino Suarez incident categorized it as a total collapse. Unless you have done some research into this particular event, or have some specialized training, education, or experience that would contradict the assessment of the engineers that have investigated it, I will have to consider your "partial" collapse statement inaccurate.

dailykoff wrote:
...I saw a photo of it and it looked to me like it had a concrete frame.

Post#2

Although, it may be accurate that you incorrectly believed that the Pino Suarez building had a concrete frame, the available information clearly indicates that it was a steel frame building. At the very least, your statement implies that the building had a concrete frame, which is quite obviously inaccurate.

-Make7

[dailykoff]

49. Thanks, and if it relieves the itching,

you can substitute "skyscrapers" for "buildings" in that first statement.

[Make7]

51. If your original statement was accurate, why are you changing it?

Even with the rewording, it is still debatable whether or not that can be considered a true statement.

-Make7

[dailykoff]

52. To ease your symptoms. No charge. n/t

[killtown]

8. What are the real facts of all those "errors"?

How tall were the towers?

How long did it take WTC 1 and 2 to collapse?

[Make7]

12. It was hard to find this information, but I finally tracked it down.

killtown wrote:

How tall were the towers?

How long did it take WTC 1 and 2 to collapse?

1368 feet and 1362 feet.

Longer than the 8.1 seconds and the 10 seconds claimed in the slide presentation.

-Make7

[AndrewJohnson]

21. How significant are the errors, though.

These may, strictly speaking, be errors, but really and honestly, how significant are they to what the conclusions are?

The official story is that Steel Beams melted or softened and the buildings collapsed largely as a result of that.

The figure of 1350 feet for the height came from the Grolier Multimedia Encylopaedia. I believe other posts here show the difference to this figure as being something like 12 feet and 18 feet respectively. Of course, it would not surprise me if the towers had been slightly taller in summer and slightly smaller in winter due to expansion of materials!

How accurate do you want it to be?

What you could have done is e-mailed me, using the link in the presentation, with an improved version - with error factors added. Taking into account what you mentioned, what would the collapse times be? Can these times be explained be the pancake theory?

That is what the thrust of what the presentation shows - that the pancake theory CANNOT be correct. Why post all this to this board? Why not just present an alternative set of data and post it somewhere? Or contact me - the author? I won't bite. If you read my posts on the Physics forum, you should realise that.

In any case, what do you think of Physics Professor Steve Jones' paper.

http://www.physics.byu.edu/research/energy/htm7.html

Does it make you think? I hope so.

[ncrainbowgrrl]

22. Hi AndrewJohnson! Welcome to DU!

:hi:

[reprehensor]

24. Hello Andrew.

I must say, that physorg.com thread is one of the most interesting reads around regarding the anomalous nature of the collapse speed and the lack of resistance.

Another poster from this site made some graphs which may be of interest to you, and tend to support your argument.


Figure 1-Large


Figure 3-Large

[AlienSpaceBat]

26. No conservation of momentum in those graphs.

In effect they are showing what would happen if a brick fell from the top of the tower, and another brick was pushed off from the level of the next floor at the moment the first brick went past. Then another brick was pushed from the floor below when the previous brick went past etc.

The problem with this is that it treats the bricks as starting their descent from rest each time - or in the case of the tower collapse as each floor fell into the next the whole thing stopped, then started in free fall with no vertical velocity.

What must happen is that the momentum that the falling mass of the upper floors has is transferred at each collision to the mass of the falling floors plus the mass of the floor that it falls into. This will slow down the fall each time, but as the falling mass gets greater and greater and faster and faster the slowing effect is reduced each time.

I posted some graphs and data tables back in that original thread, 2 of which are here:

Collapse of floor 110 onto floor 109 and onward, total time 15.2 seconds:



Collapse of the top 30 floors as a block falling onto floor 89 and onward, total time 9.7 seconds:




Its important to note though that these times are the absolute fastest that the structure could collapse by pancaking and conserving momentum. In the real world the times *must* be greater than I've given for both scenarios.

There is no allowance for crushing and breakage of internal supports, air resistance, or any energy diverted into pulverising concrete and other materials, or translated into horizontal movement of debris. Any of these would add some significant slowing of the whole process, but I didn't include factors for them as I don't have the knowledge to accurately estimate what these would be.

[AndrewJohnson]

35. Thanks

Thanks for the info. For those that think that all this is a "Conspiracy Theory", I have to mention that Eisenhower, in my view, warned us about what he saw was underway in 1961, when left office:

“In the counsels of Government, we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the Military Industrial Complex. The potential for the disastrous rise of misplaced power exists, and will persist. We must never let the weight of this combination endanger our liberties or democratic processes. We should take nothing for granted. Only an alert and knowledgeable citizenry can compel the proper meshing of the huge industrial and military machinery of defense with our peaceful methods and goals so that security and liberty may prosper together.”

He also said (in the same speech):

Today, the solitary inventor, tinkering in his shop, has been over-shadowed by task forces of scientists in laboratories and testing fields the same fashion, the free university, historically the fountainhead of free ideas and scientific discovery, has experienced a revolution in the conduct of research. Partly because of the huge costs involved, a government contract becomes virtually a substitute for intellectual curiosity.

For the full address see here:


http://www.historytools.org/sources/farewell.html

[petgoat]

57. Wow! So Ike is warning not just of the MIC, but the

military-industrial-university complex.

I Like Ike! Welcome to DU!

[Make7]

25. I think some of them are significant.

My main issue with the slide presentation is that one of your main arguments is that the towers could not have collapse by the jet impacts and fire because they collapsed too rapidly.

I will agree with you that the height difference you used for the towers does not significantly alter the theoretical free-fall times calculated, but I very much disagree that the actual collapse times that you have used are accurate. There is widespread disagreement of what those times really were between people that have done research on the subject. I don't think you can really make the claim that "these events are recorded on video and are indisputable" when talking about the collapse times you have given. It is very difficult to precisely discern the endpoint of the collapses because of the dust and debris. Also, the resolution is often poor on many videos, making the exact beginning of the collapses inaccurate as well. Therefore, I believe the collapse times are very much disputable, and quite likely impossible to determine with pinpoint accuracy.

Here is someone with very different collapse times based on video evidence:

ERROR: 'The Towers Collapsed in 10 Seconds'

Each of the Twin Towers totally collapsed in an interval of approximately 14 to 16 seconds. A temporal record of the entire North Tower collapse is provided by the real-time CNN broadcast feed aired during the attack. (This table shows frames from that video at half-second intervals.) It allows reasonably accurate measurement of gross collapse features such as the growth and descent rate of the rubble and dust cloud. However, this and other video evidence does not allow the determination of a precise time of total collapse because each tower's destruction remains hidden behind an expanding dust cloud which, because of its size, reaches the ground over a span of several seconds.

Despite the availability of video evidence establishing lower bounds of total collapse times of over 13 seconds for each of the towers, assertions that they collapsed in under ten seconds are widespread. Collapse times of eight to ten seconds are common not only in literature of the skeptics, but also in publications promoting the official explanation. A Scientific American article about a 2001 public meeting of engineers on the MIT campus in Cambridge, MA gives a figure of nine seconds.

http://911review.com/errors/wtc/times.html

They seem to believe the indisputable video evidence gives a far different time than what you have claimed.

"What you could have done is e-mailed me, using the link in the presentation, with an improved version - with error factors added. Taking into account what you mentioned, what would the collapse times be? Can these times be explained be the pancake theory?

That is what the thrust of what the presentation shows - that the pancake theory CANNOT be correct. Why post all this to this board? Why not just present an alternative set of data and post it somewhere? Or contact me - the author? I won't bite. If you read my posts on the Physics forum, you should realise that. - AndrewJohnson

I don't know you, why would I bother to email you about this? Do you feel that I should search the entire web for factual inaccuracies and then email the authors of the webpages?

I post all this to this board because I am a member here, and I like this forum. I don't really care one way or the other if you do or do not bite - I come here to discuss things on DU. Now that you're here we can talk about it if you would like.

Welcome aboard. :hi:

-Make7

[dailykoff]

28. Don't worry, there aren't any.

1350' (to top floor) is a perfectly acceptable measure of building height and the collapse times are necessarily interpretive.

[Make7]

31. You don't think the full height of the building should be used...

... to calculate the theoretical collapse time of the building? If not, then perhaps it should be pointed out that the collapse time calculated is only from the top floor, not the top of the building.

The collapse times are definitely open to some interpretation. Perhaps you could show us a video of the North Tower that could reasonably be interpreted as collapsing in 8.1 seconds?

-Make7

[dailykoff]

32. He's using the full height.

You're quibbling about how he measured it. Why, I don't know, because the more conservative figure produces a slightly less dramatic argument. But it's completely immaterial to his conclusion.

[Make7]

37. Which one is the full height?

dailykoff wrote:

There are several ways to measure building height, to top of roof and to top floor for example, and 1350' measures the latter.

Post#2

Wouldn't the measure to the top of the roof be the full height of each the Twin Towers? Would that not be the proper height to use to calculate the theoretical collapse time?

The main complaint I have about his slide presentation is the collapse times used. Do you have a video clip that shows the 8.1 second collapse time for the North Tower?

-Make7

[dailykoff]

40. 1350' is the full height

to the top floor. For the purpose of this discussion, it doesn't make the least difference how the height is measured, ditto the exact number of seconds. The buildings fell at top speeds no matter how you clock it.

[Make7]

42. But not the full height of the building.

Isn't the theoretical collapse time supposed to be calculating the time for the whole building to collapse?

Here are the rates of acceleration for a few different collapse times of the North Tower:

 time     rate of acceleration
8.10 s        41.70 ft/s2
9.22 s        32.16 ft/s2
14.2 s        13.57 ft/s2
16.2 s        10.56 ft/s2

How are you defining "top speeds"? What is your basis for comparison?

Just saying that something doesn't matter does not make it true. The main argument in the flash presentation is that the actual collapse times were too fast compared to the theoretical collapse times, thereby "proving" controlled demolition. But you seem to be contending that accurately determining these times is not important. I would think if one were to make a case based on something, one should try to present it with a reasonable degree of precision.

-Make7

[dailykoff]

44. It's the full height of the buildings,

measured from first floor to top floor, as I've explained at least three times. Now before you break out in hives consider that to come up with a useful measurement you have to draw the line somewhere, and there are many points to draw it, such as top of antenna, top of structure, top of roof, and top floor, to name a few.

p.s. about the collapse times: the fact that there was any movement, at free-fall acceleration or otherwise, of the structure below the crash floors is in my view proof that explosives were used to demolish the buildings. There is simply no other credible explanation for the simultaneous disintegration of all that steel, and the NIST has not provided any.

[AZCat]

45. Perhaps your understanding of dynamic structural loads...

is lacking if you don't believe there is any other credible explanation for the collapse.

Why do you feel qualified to make such a bold assertion?

[dailykoff]

46. I already danced a Dynamic Duet

with the lovely hack89 here:

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=63126&mesg_id=63452

But it sounded too much like the Progressive Collapse Calypso, and so we waltzed away.

[Make7]

48. Thank God for Diphenhydramine!

From my first reply to you in this thread:

I wrote:

I assume that you realize the reasons there are different measures of building height. Which one do you feel should be used for calculating the collapse time of a building?

I suppose I should thank you for pointing out in your most recent post that there are different ways that building heights are measured. (Who knew?)

Perhaps if you would have come up with a reasonable response to my original question, you might have saved me from the risk of breaking out in hives.

-Make7

[dailykoff]

50. Try not to scratch when you hear this,

but for purposes of this discussion, I don't think it makes the least difference how the height is measured. Or did I already say that?

[LARED]

29. The errors make the whole argument null and void

The entire 9th grade lesson in physics is moot because the collapse time are completely wrong.

End of story.

[AndrewJohnson]

34. Stopwatch?

The collapse times are accurate to within < 5 seconds. Here is a video for you to watch which measures the collapse time. See what you make of it (8 minutes long)

http://www.checktheevidence.com/AreTheCriminalsFrightened.wmv

Get your own stop watch and see whether you think it is 8,9,10,11,12 or 13 seconds. Let's say its 13 seconds. You think 110 floors of steel and concrete can basically just collapse with not-enough-jet fuel in 4 seconds? That's basically what the pancake theory says. You can agree the pancake theory is correct if you want - I will never agree with you until someone shows me better evidence.

Also, there are similar posts to yours on the Physics forum which say the physics is wrong, but they don't really show why - one person suggested a collapse time was 22 seconds. This is not supported by the video evidence.

Also check building 7 which wasn't hit by a plane and also collapsed into its own footprint:

http://www.checktheevidence.com/WTC7.wmv (2 minutes)

By the way, I am in the UK so "9th Grade" means nothing to me, I'm afraid. But for myself, I graduated in 1986 with a degree in Computer Science (major) and Physics (minor).

[LARED]

38. I have numerous videos

of the towers collapsing from right after 9/11/01. I would guess the total collapse time to be somewhere around 15 to 20 seconds. It is very difficult to determine an accurate time because of all the dust generated during the collapse. That means the time is approx 50 to 100 percent longer than used in the presentation. A significant difference. If you want to see how much difference it makes calculate the free fall distance for 20 seconds. It's almost 2000 meters.

The use of the equations of equations is fine, but your incorrect premise on the collapse times invalidates the conclusions.

BTW 9th grade is the first year in high school in the states. Most 9th graders can take a physics class that cover the basic laws of motion.

[Rich Hunt]

7. A good resource...

Is the Time-Life DVD, World Trade Center : Anatomy of a Collapse. It uses computer models, footage of salvaged steel, and interviews with engineers.

Here are some screencaps from the DVD that may help you.



This first one is a model of the impact zone, North Tower. It shows the damage that was done,
complete with floors knocked out.




-----------------



This is a model that shows what happens between two intact floors when the
floor in the middle is knocked out. Notice the weights on top.



------------------



This is a computer model of the floors collapsing



==============



Here you can see the south tower collapsing at the point where the most damage was
done.



--------------------



Here is an example of twisted steel from the WTC:





Distorted brackets from the WTC:




--------------------

I've got lots more, too, if you're interested. I hope these turned out okay.

[dailykoff]

10. thanks Rich!

Very interesting photos!

About that model, though -- the height-width ratio appears to be wrong by a factor of about 20,000%, and it's missing a core.

[Rich Hunt]

53. that wasn't the point, though

It was just a simple illustration on how weight is distributed in skyscrapers. I learned about this in introductory architecture classes - take out the middle floor, and the exterior support structure is less rigid and weakened. As far as the core of the WTC, that wasn't the main support mechanism.

You don't seriously think it was meant to be a scale model of the World Trade Center, do you? It is a model of three floors with exterior support columns - take out the middle floor, and the exterior columns are weakened.

[dailykoff]

54. Yes Rich, I do think that.

I think every frame of the program (which I'll admit I didn't see) is intended to reinforce the false notion that the Twin Towers collapsed "naturally" as a result of the plane crashes and fires.

Sure, when you parse the transcript, you may find that Dr. Eagar or whoever is simply expressing an opinion, not explaining what actually happened, or that this is a model of such-and-such and not what it clearly looks like -- a pair of buildings having more or less the proportions of the twin towers but conveniently lacking everything that held them up, namely 287 (not 4) perimeter and core columns on each of 110 (not 2) floors.

The intended effect is for the viewer to think, "Sure it happened that way! I saw a model on TV and it collapsed, so why not the real thing?"



I also think it's pretty effective.

[Make7]

55. more or less

dailykoff wrote:

... what it clearly looks like -- a pair of buildings having more or less the proportions of the twin towers ...

Post#54

or...

dailykoff wrote:

About that model, though -- the height-width ratio appears to be wrong by a factor of about 20,000% ...

Post#10

Which one is it?

-Make7

[dailykoff]

56. Both, which is why it's deceptive.

Visually, the models resemble the WTC towers, but structurally, they have a column to floor height-width ratio of about 2:1, while the towers had a ratio of about 12:200, a difference of about 3,200%.

I was off by a decimal point, so sue me.

[Make7]

58. Even though it was never claimed to be a model of any part of the WTC?

It was a model used to illustrate a concept and designed for that purpose. To claim that it is not representative of the Twin Towers, or any part of them (or both) is somewhat disingenuous.

dailykoff wrote:

I was off by a decimal point...

Actually, it looks like you were only off by 625%. (Based on your calculations.) Taking into account what you consider to be accurate, I'd say that's impressively close for you.

-Make7

[petgoat]

59. you were only off by 625%.

koff said the model had a 2:1 height/width ratio and the building has a 12:200 ratio.

Koff said the discrepancy was 3200%.

12/200 = 0.06
2/1 = 2

2/0.06 = 33.33 = 3333%.

[Make7]

60. That's mighty impressive.

However, he/she previously stated that "the height-width ratio appears to be wrong by a factor of about 20,000%". (Post#10) And then said the discrepancy was 3,200%. (Post#56) So, using those numbers, that gives us:

   20,000% / 3,200% = 625%

I apologize for not being clear enough, although I was responding to dailykoff and assumed that what I was commenting on was sufficiently clear to the intended recipient. One clue as to the meaning of the 625% figure is the following quote: "I was off by a decimal point, so sue me." (Post#56) Which, of course, was also incorrect.

-Make7

[dailykoff]

61. No need to apologize.

I can't figure out what nit you think you're picking half the time anyway. :)

[Make7]

62. I was not apologizing to you.

That's why that response was not to one of your posts.

You seem unable to figure many things out - glad to see that your lack of comprehension doesn't discriminate.

-Make7

[WeedBug]

9. My Story

2 Days before the September 11 attacks I rang a nationwide talkback show in New Zealand. I forget how the conversation started but after only a couple of sentences I started saying "they dont think". I said this three times. Ill let you imagine who i was talking about. The next thing I did was yell at full volume "WAR" meaning there was going to be one. After this I gave a cry to tell about suffering (er youd have to hear it and what the host was saying) and then showed that I was giving the call everything I had and started saying "the thing, the thing" as a clue to why i was saying there was going to be a war. I finished the call by voicing a gleam in my eye, referring to there going to be a war and what i was saying about it. Err i guess you know what a gleam in ones eye means. So 2 days after yelling theres going to be war the planes hit the buildings. Theres more to the call than this like the host speaking and stuff but its obviously hard to type about a phone call and deliver the exactness of it. I made a point of showing I was giving it everything I had to express how there was going to be a war and everything in the call was to do with war. Umm, the translation of the call into text is a very poor example but i just wanted to post that and see if people have any comments. Like I said its not nearly as powerful as it would be to hear the actual call.

Thanks

[rman]

15. Afaik the claim of the Official Story is not that the steel beams melted,

(though some supporters of the O.S. do claim that) but rather that they were weakened by the fire.