Free-Fall Collapse

I have heard good things regarding the integrity of this message board. So, lets put this reputation to the test. I am a physicist and I will not give away my credentials (several good scientists have already lost their jobs). I am a first time user, and I would like to talk about some real topics. If by real you assume I mean an inevitable response of "you are an asshole", please don't bother, as I will not even take the time to respond to such idiotic comments.

That being said, lets get straight to the topic at hand, which is, of course, the collapse of WTC buildings 1,2 and 7. As far as I am concerned, the most important topic that I have encountered regarding "9/11 truth" is the free-fall, symmetric collapse of WTC buildings 1,2 and 7. We all know that buildings 1 and 2 fell in approximately 10 seconds, while building 7 fell in approximately 7 seconds. Most interestingly, all of these buildings fell VERY close to the speed you would expect an object experiencing ZERO resistance to fall, according to the high-school physics equation x = 1/2 at^2. This simple fact, of course, doesn't make any sense at all, because you would expect that if there was ZERO resistive force in the way of the respective collapses, THE BUILDINGS SHOULD HAVE NEVER STOOD IN THE FIRST PLACE.

That fact is obvious, as far as I can see (if you are a physicist, I don't see much point in arguing that, unless of course you regard the basic laws of physics as 'conspiracy theory', as I'm sure many uninformed individuals do).

That being said, we are left with a simple, yet important question - What if the measurements of collapse time were not accurate? Well this is certainly plausible, but, would it matter? I don’t think so -

For example, towers 1 and 2 were about 413 meters tall. Each tower was 110 stories high. So, each floor was about 3.8 meters high (basic mathematics, not conspiracy theory). Lets now assume, extremely conservatively (no pun), that each floor experienced 1/3 the resistive force that we know existed, since the building stood in the first place. This assumption equates (quite trivially) to an acceleration term of ~ 6.5 m/s ( 1/3 of 9.8 (experimentally measured acceleration due to gravity) = 3.3 m/s and 9.8 - 3.3 = 6.5 m/s). So, we calculate an equation of position x = 1/2(6.5)t^2 - where t= time, and x = distance. Wonderful, moving along quite like a second grade physics course. Well, since we know that each floor is about 3.8 meters high, we have that

3.8 = 1/2 (6.5)t^2 and thus -
t = sqrt (7.6/6.5) = sqrt(1.2) = 1.1 seconds, for EACH FLOOR.

So, WTC 1 and 2 are 110 stories tall - thus, we have a total, reasonable (not really since we assumed the building SHOULD NEVER HAVE STOOD), collapse time of 119 seconds, or, about 2 minutes.

Well now, what if the measured collapse was really 13 seconds, or 20 seconds instead of 10??? It doesn't matter. With 1/3 the resistive force KNOWN TO EXIST, the buildings shouldn't have collapsed in less than about 2 minutes. Clearly there is something wrong here. An equivalent calculation can be applied to building 7 with similar results. The collapse times are absurd.

The only reasonable theory that fits all the data, including free-fall, symmetric collapse as well as molten metal hot spots - is controlled demolition. To deny this hypothesis as a scientist is akin to saying - "Alright, all the experimental and theoretical evidence supports quantum theory, but, hell, I don't like it, it can't be right". In the words of the late great Richard Feynman, "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong". I'm sorry to emphasize, once again, the only theory that agrees with experiment and theory is controlled demolition.

It is truly time to wake up.


- J
*Caps Lock title edit

[edit on 9-11-2006 by dbates]

Please explain how you came up with a value for the "resistive force."

What are the units?

How did you calculate it?

Where did you get your data that you used to imput into your calculations?

Does the value change if you change or modify the design of the building?

Thanks.

I'm certainly no physics expert. I had to read your post about three times to get the gist of what you're saying.

So you think the buildings fell too fast and that could only be the result of a controlled demoliton right? You're saying they should've fell in 2 minutes? Does that have to take into account any weight?

Would you mind explaining "zero resistance" a little more? Thanks.

Originally posted by JB1975
I am a physicist and I will not give away my credentials (several good scientists have already lost their jobs).

- J

I'm not arguing your point, but how could you lose your job by listing them? Do you have such specific education/experience that by listing them you would out yourself.

I'm interested in your thoughts but with no references your ideas are as speculative as mine would be.

The Towers didn't fall at free fall speeds.

www.911myths.com...

This report actually takes into account accurate measurments of the height, weight and other building specifications of the Trade Towers.

Here are some other relevant pages:
www.911myths.com...
www.debunking911.com...

I'm not physics expert either but your calculations are seriously off.

Have you taken things like weight and transfer of momentum into account?

More on Greening:

Frank R. Greening was born in London, England in 1947. He has a Ph.D. in physical chemistry and has carried out research in physics, chemistry, and materials science for 30 years in academic and industrial positions. He has published approximately 80 research reports and journal articles, including numerous articles supporting the government’s collapse sequence theories of World Trade Center Buildings 1 & 2.

It's interesting that scientists that challange the "Official Story/theory" are losing there jobs, I wonder why, to discredit there findings. Oh there just a crackpot that got fired from their position.

And as it has been stated really well in the first post, this collapse goes against what we know about basic physics.

People cannot accept such a terrible truth, I think many Americans are in a cronic state of denial. Like a parent who's child is bad, not my little Johhny he would never do that.

Brainwashed from childhood to support the American structure of power right or wrong. Reminds me of Germany in the the late thirties and early forties, false flag Ops and all.

Originally posted by elaine
So you think the buildings fell too fast and that could only be the result of a controlled demoliton right? You're saying they should've fell in 2 minutes? Does that have to take into account any weight?

If you're thinking that the upper floors were too heavy for the lower floors, this doesn't stand up. The uppermost floors, aside from being so much smaller than the lower structure, were also less dense for structural reasons. It doesn't matter HOW much weight was falling straight down, realistically. It would have at least slowed down. The fact that the caps were so much smaller and STILL didn't slow down, the whole way down, should tell you something.


JB1975,


I think you'll find with WTC1 and 2, that a collapse speed was maintained slightly under free-fall the whole way down, with no accelerations, and that the collapse times total come out around 18 seconds.

Not sure on the rest, with a quick glance, whether you're resetting the free-fall acceleration at each floor or continuing it from floor to floor with resistance constantly applied. It should just come to a halt, if done realistically, imo, as the resistance was constant and not floor-to-floor, as if there would be enough available energy at each floor to take it out to begin with.


For WTC7, it would be more useful to find a way to calculate a velocity from the collapse videos, because I'm already seeing the 'debunkers' fix the free-fall issue by timing the collapse earlier. Thus, revert to the velocity itself and that argument falls apart.

My two cents, I may add more later. Haven't really looked at the whole post in that great of detail yet.


Edit: Greening!

Greening's calculations are ATROCIOUS!

He assumes ALL of the mass falls STRAIGHT down, that the momentum is RESET (impossibly!) after each floor so ALL of the energy is used right at the collapse wave, rather than being transferred down the building, etc. All theoretical, all unrealistic, all impossible. Gordon Ross has had exchanges with Dr. Greening over the Journal of 9/11 Studies, and if you read without bias you'll see notice some serious flaws. Just the fact that Greening assumes all mass goes to crushing each floor, when a more realistic average of ~10% went towards it is a hint enough that this man's mathematical model does not apply to the actual event.

[edit on 8-11-2006 by bsbray11]

I will not address science in this post but will merely use my own eyes, ears, common sense and logic. The fall of the WTC, specifically WTC7, cannot be explained away as having occurred due to fire and structural damage. It is not possible for fire to disintegrate a steel structure and reduce it to ashes inside its own footprint. I will not detail the already heavily cited "evidence" such as Silverstein's comments, the NYU medical student who heard a "clap of thunder" and a "shockwave" rip through WTC7 seconds before its collapse or any of the other eyewitness testimony.

I simply cannot believe that 3 buildings vaporized into pulverized concrete as a result of 2 planes. The math doesn't add up. The lesser WTC buildings which had the twin towers fall directly onto them did not collapse and had much greater fires and structural damage than WTC7.

It's like watching the Zapruder video and still believing that a magic bullet made several right angle turns and pauses in mid-air as it pierced through two people in the motorcade.

Seriously, its time to wake up America. Your government is playing musical chairs while the people's seat at the political table is being pulled out from under your electronic vote. 9/11 must be fully explained away for it is the staple of all the policies that have come since. Afghanistan, Iraq, Patriot Act, Military Commissions Act, Real ID (2008), and a host of other domestic and foreign departures away from what made America the land of liberty have since been implemented because of 9/11.

A true democracy must be transparent. Why classify dozens of videos showing the impact at the pentagon? How could that be a national security issue? Wasn't the actual breach and subsequent attack the real national security dilemma?

There are dozens upon dozens of questions that need to be addressed by an independent commission that will at least consider all possible explanations (i.e. controlled demolition) for the events of that day. Until such an investigation is launched, the American people have the right to protest and object to the official version of events.

I bet Chief Justice Warren is smiling somewhere, thankful that the Internet and digital age did not exist during the Kennedy coverup.

[edit on 9-11-2006 by Ordo Ab Chao]

[edit on 9-11-2006 by Ordo Ab Chao]

Originally posted by Blue_Jay33


People cannot accept such a terrible truth, I think many Americans are in a cronic state of denial. Like a parent who's child is bad, not my little Johhny he would never do that.

Brainwashed from childhood to support the American structure of power right or wrong. Reminds me of Germany in the the late thirties and early forties, false flag Ops and all.

That's not always true. Some of us just want more solid proof and to finally know what really happened.

That's why some of us question. Questions aren't always to "debunk" someone. Sometimes it's simply to understand better what the theories are so that we can deliberate them for ourselves.

I will add that when I watched the collapse of the towers, it was truly amazeing to me just how fast they fell.

Good post! Exactly what I've been arguing all along. Free fall or not it doesn't matter.
Free fall is just like saying, 'it may as well have been for all the difference it makes.'

If it was even possible for the towers to have collapsed vertically straight down on itself it would have taken a lot longer than 10 secs or 20 secs or even 60 secs.

So trying to argue that it wasn't 'free fall' is a waste of everyones time.

Too much of the physics of the WTC collapses points to there having to have been another force acting on the towers other than fires and damage from the planes impact.

You can't argue with the physics.

Originally posted by bsbray11

Originally posted by elaine
So you think the buildings fell too fast and that could only be the result of a controlled demoliton right? You're saying they should've fell in 2 minutes? Does that have to take into account any weight?

If you're thinking that the upper floors were too heavy for the lower floors, this doesn't stand up. The uppermost floors, aside from being so much smaller than the lower structure, were also less dense for structural reasons. It doesn't matter HOW much weight was falling straight down, realistically. It would have at least slowed down.

Thanks for the explanation bsbray11. I see what you're saying.

www.911myths.com...

Did anyone even read that?

The author uses mathematics and science to prove that the Trade Towers fell in the exact amount of time they would have according to the official story.

Free fall or not - the towers fell in the amount of time identical to a pancake collapse.

Yes, Fungi:

Originally posted by bsbray11
Edit: Greening!

Greening's calculations are ATROCIOUS!

He assumes ALL of the mass falls STRAIGHT down, that the momentum is RESET (impossibly!) after each floor so ALL of the energy is used right at the collapse wave, rather than being transferred down the building, etc. All theoretical, all unrealistic, all impossible. Gordon Ross has had exchanges with Dr. Greening over the Journal of 9/11 Studies, and if you read without bias you'll see notice some serious flaws. Just the fact that Greening assumes all mass goes to crushing each floor, when a more realistic average of ~10% went towards it is a hint enough that this man's mathematical model does not apply to the actual event.

I suppose you can slap numbers around anything and call it "proof" and it suits you ok, right?

Because I could do the same. I don't because I actually realize how hard it would be to accurately portrary a collapse mathematically. Adding one floor to the next to the next and assuming a total lack of resistance from an overpowering force that you're ALSO assuming is just flat-out bad science.

The Journal of 9/11 Studies, where Ross's papers are hosted: www.journalof911studies.com...


And, I also did an article on just ONE of Greening's faulty assumptions here: www.studyof911.com...


Put short, Greening assumes no resistance and a final product of this:




Ie, 100% of the mass goes towards a collapse, straight down, each floor "condensing" into a solid object of twice the mass. Sound realistic? The correct answer should be NO.

In reality, there was mass to provide a LOT of resistance, and the final product was more like this:




Via these:






As stated in that paper,

I will show that calculations such as Greening’s should be adjusted so that the masses of both Towers are steadily and consistently removed during their collapses so that at least 80% of the total building masses will end up outside of their respective building footprints by the completion of their collapses (which assumes the final resting masses within the footprints constituted 20% of the total building masses, something which is seriously doubtful and therefore generous to Dr. Greening’s figures), rather than Greening’s assumption that 0% of the total masses was moved outside of the footprints, and that 100% stayed within them to contribute additional mass to the collapses of the trusses and their connections to the core and perimeter columns on each floor with an impossible amount of efficiency. This would obviously greatly impact figures such as any on floor momentum transfers during the collapses, even without additional considerations of Greening’s work. (Gordon Ross already has a paper outlining another error in Greening’s calculations, which allowed Greening to reuse energy already transferred down the building multiple times. This paper can be found here.)

And the link on "here" is to this URL: worldtradecentertruth.com...

[edit on 9-11-2006 by bsbray11]

Anyong who doubts the 10 second collapse time needs to look at the documented seismograph readout that was Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, 21 miles north of the WTC.



Suspending laws of physics,even if aviation fuel was miraciously able to melt steel uniformly around each steel collumn, the pancake theory is bull. top 20 odd floors falling onto the bottom 90, even at half a second per floor of resistance time would mean a fall time of 45 seconds.

War games like vigilant guardian being carried out on 9/11. this means all the good americans in charge of radar etc on that day did not need to be in on it. they were standing down on higher orders because they were being told it was a dummy run. it is ridiculous to suggest thousands of honest americans would have to be in on it. (o'reilly opinion)


Explosions prior to collapse reported by NYPD+FDNY+public which were also picked up on in the seismograph.


Melting steel days after the attack, six floors down in the basement.


Mohamed Atta's passport fount on the ground in manhattten (lol)


Impossible mobile/cell phone calls from 30,000 ft


Marvin P. Bush, the principal in a company called Securacom that provided security for the World Trade Center, United Airlines, and Dulles International Airport. (another co-incidence?)


Numerous reports of 7 hijackers still alive.


No arab names on the flight passenger manifest list.


STAND DOWN for over an hour and a half by arguably the best militry defence system in the WORLD (jets could have been there in 2 MINUTES)


Look who gained from this terrible event!no muslim i know(patriot act anyone?)


The forgoten osama (911 is not even mentioned on the FBI most wanted page for bin laden because there is no evidence against him)

It continues to amaze me the length your average person will go to in order to defend their governments story (even though it was anounced days after attack with no proof: still none!) Maybe the very thought that your taxes may have paid for the undertaking of 911 rather than 'al-quaida' money is just so abhorent we subconciously block it from our minds.

"Statesmen will invent cheap lies, putting blame upon the nation that is attacked, and every man will be glad of those conscience-soothing falsities, and will diligently study them, and refuse to examine any refutations of them; and thus he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception."
- Mark Twain

All that flag waving on 911 made me sick! flying the UNITED STATES (a corporation not even a country) flag at the brave men of the FDNY+NYPD, when it was the same flag the criminals who carried out the attack hide behind.

George Washington said, "Let the 13 stars in a circle stand as a new constellation in the heavens."

Its not just americans who have this problem, here in the UK we are even further away from coming to accept that our government was involved in the London bombings. At least the 911 truth movement gets a mention on the news in the US.

A very skillful use of manipulating culture makes us brits laugh at your ridiculous FOX, all the while the BBC manages to keep its stern professional image we trust so much (I heard one daily mail journalist say the 911 truth movement must be wrong because "the bbc wasnt talking about it" - this is ultimate opinion control.)

We live in a world where our justice system is very astute and stringent when it comes to a murder trial (proof beyond reasonable doubt etc) but no court case of evidence is needed to go and start another war (well made mind controlling propaganda will do)

We need to respect the honour of the people that died that day and stop listening to politicians lies, rather than tarnish the memory of their deaths by using it as an excuse to go and kill more innocents in u

Hello JB and welcome to ATS.

The towers didn't fall at freefall. Various videos have been used that give multiple sources for the tower fall time for WTC 1 at least (and I do believe it can be done with WTC 2 but I'll stick with what I know). The videos show the tower falling in an approximate 16 second time period. Some other site as claimed it is 14 seconds, but I personally haven't seen any video evidence that supports that number, but I've worked with two separate videos that both back 16 seconds.

I mostly read and don't post much. I'd rather not share my views on 9/11 - though I have my own theories - because a many of the people who post here have much more compelling arguments and qualifications than I.

The only input I have at this junction is not having to due with 9/11 so much as to bsbray11. Keep up the good work. Everytime I doubt I'm correct, I can read a few of your posts and I am completely rejuvenated.

[edit on 10-11-2006 by white4life420]

Originally posted by white4life420
The only input I have at this junction is not having to due with 9/11 so much as to bsbray11. Keep up the good work. Everytime I doubt I'm correct, I can read a few of your posts and I am completely rejuvenated.

Just as a side note. As much as I agree with BSBray11, you should really look into things yourself. No offense BSB. You're right that BSBray11 has taken alot of time out of his life to enlighten all of us. But to be fair...look into the other side also. I don't know why I feel compelled to give you advice? Anyway, I'm glad you're trying to figure out 9/11...either with the help of others or by yourself. Also, I do agree, BSBray11 has done a great job. So has WeComeInPeace (BTW, can you change your name...it's hard to type...lol). I have to give these guys a great deal of appreciation. Also, Vallhall is another great poster. And I do have to say that HowardRoark, LeftBehind and others are great debators and make me think. Anyway, take care and feel free to post your opinions. No one will bite your head off.

Edit: Forgot to mention Labtop's posts.

Edit again: Err...forgot JB also...keep up the good work...I gave you my last vote for the month.

Edit 3: One of these days, I'll get it all out in one post. I have voted HowardRoark and LeftBehind at times also. Just so people don't think I'm biased. I am, but if someone shows some good research, they desearve a vote IMO.

[edit on 11/10/2006 by Griff]



[edit on 11/10/2006 by Griff]

[edit on 11/10/2006 by Griff]

Yeah, should definitely check things for ourselves. I try to drag in as many sources as I can (at least when its convenient for me lol) so people can check things back for themselves, which is why I included the FEMA (Figure 1-7, from the introduction, chapter 1, of that report) and NOAA (from a satellite scan they took on Sept. 23rd and hosted on their site -- HUGE image though, 14 MB) images above, not that the other images look like they've been photoshopped or anything. That way nobody has to take my word for it. If we all did that then these discussions would go so much more logically. But when something is asserted that hasn't been well established, then yeah, by all means that needs to be questioned.