Tuesday, May 09, 2006

Free Fallin'

James has alread discussed one of the problems with the claim that the buildings fell as fast as if they'd been in free fall, namely that Avery estimated the free fall time based on the height of the roof, when in fact the buildings collapsed from where they were hit.

There's a rather simple way, though, to show that the buildings did not come down in free fall. Here's a screen shot from Loose Change at 9:57, showing the collapse of the South Tower:



What do we see? Think about the World Trade Center and the debris falling from it as an umbrella. Here's another shot that gives you an idea of what I'm talking about.



What is clearly evident in both these photos is that the debris field in general is falling faster than the building. This creates the umbrella effect. In spots where there is visibility through the debris field we can see that the building is intact higher than the debris. But if the debris is falling faster than the building, what does that mean? That the towers did not come down in free fall. They came down fast, to be certain.

Update: Commenter CV-PHD points out this section (PDF file, see page 196) in the NIST:



I still say the above photos show that the building was not coming down in free fall, but since the experts say it was "essentially" free fall, this seems to be a minor point; someplace where the experts and Loose Change are "essentially" in agreement. I guess the obvious question is how fast do buildings that are being demolished come down; do they come down in essentially free fall as well?

It is argued here that the collapse time is more like 15 seconds while free fall would have been more like 9.2 seconds. In an oddity, Loose Change purports to clock the time the building took to fall (at 35:55 of the film), but they don't show the total time; instead the clock fades out after measuring about 10.23 seconds:



(Click on picture to enlarge; you can barely see the numbers 10:23 in the bottom center). There is an open question as to whether Avery started the clock at the right time as well; looking at 35:55 in the movie it certainly appears that the time is close to 10 seconds, but check out the earlier view of the collapse at 35:22. The collapse is clearly underway (note the top of the building leaning slightly to the right). Now just watch the film and check out the running time. At 35:32, when the building should be completely down according to Avery, we can see that it's still nowhere near the street. Indeed, the debris field (which was ahead of the structure) is now only at the level of some of the rooftop of some of the smaller buildings:



Indeed if you watch the version of the collapse at 35:22, it appears to end around 35:37, which fits pretty neatly with the 15 second estimate by 911 Myths.

10 Comments:

At 09 May, 2006 10:30, Blogger Seabhcan said...

They fell at 'near free fall' according to the NIST report, NCSTAR 1-6 section 9.3.3: "the building section above came down essentially in free fall, as seen in the videos."

 
At 09 May, 2006 11:12, Blogger ScottSl said...

Just look at the videos.
Both building fell in about 15 sec
Thats about 50% more than freefall.
Freefall is 9.2 sec.

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

 
At 10 May, 2006 09:19, Blogger JoanBasil said...

9.2 seconds or 15 seconds --- awfully fast when there should have been resistance from the floors below. If you drop a heavy object on another object thats 3 times as heavy (probably more than that in this case, the top 30 floors onto the bottom 70 floors plus), do you expect the WHOLE thing to implode into dust like that?

 
At 10 May, 2006 11:40, Blogger Seabhcan said...

I think time of collapse is actually unimportant. The important point is that the speed wasn't constant, it was accelerating. A pancake-style collapse should quickly reach a terminal velocity and stay there. Only freefall can explain acceleration. The Nist report tries to glue freefall and pancaking together but they can't stick. So what does explain freefall? I don't know.

 
At 10 May, 2006 20:57, Blogger fo0hzy said...

joanbasil: If you drop a heavy object on another object thats 3 times as heavy (probably more than that in this case, the top 30 floors onto the bottom 70 floors plus), do you expect the WHOLE thing to implode into dust like that?

This video of an F4 Phantom jet ATOMIZING as it hits a wall should give you some idea of the forces at work (and should be required viewing for any Pentagon CTs)...

Hundreds of thousands of tons of concrete falling in upon itself will create a lot of dust, yes.

BTW, watch the video again - you can actually see the tips of the wings continue on past the concrete block.

 
At 11 May, 2006 06:20, Blogger JoanBasil said...

fouhzy,
Thank you for the video but how would you find that comparable to the World Trade Center? It seems like apples and oranges to me.

 
At 24 May, 2006 11:00, Blogger Alex said...

"If you drop a heavy object on another object thats 3 times as heavy (probably more than that in this case, the top 30 floors onto the bottom 70 floors plus), do you expect the WHOLE thing to implode into dust like that?"

If they're both solid objects, no, but that wasn't the case. You ever see a martial artist break 5 concrete blocks stacked on top of eachother? It's the same principle. If the martial artists put 5 blocks directly on top of eachother, he'd break his arm before he broke the blocks. But even just a tiny bit of space in between them, say, two pencils between each set of blocks, is enough to massively decrease the ammount of force needed. The WTC was 90% air, so yeah, if I dropped the upper third of the building onto the bottom two thirds, that's exactly what I would expect to happen.

 
At 22 July, 2006 06:09, Blogger R7N7 said...

If I dropped the upper 30 floors onto the lower 70 floors, I'd expect the top 30 to meet some resistance, and probably just topple over leaving a number of floors standing.

If you drop one giant hunk of concrete onto another giant hunk of concrete they both don't turn to dust. Please, someone explain to me how when the collapse started there was explosive force (debris and crap being flung from the windows) and simultaneous failure of all 47 steel columns.

If the building simply weakened and collapsed, it wouldn't expel much debris at the beginning as the top has almost no momentum, why is there so much debris flying out from the building so early in the collapse?

 
At 20 February, 2007 00:13, Blogger Max said...

If I dropped the upper 30 floors onto the lower 70 floors, I'd expect the top 30 to meet some resistance, and probably just topple over leaving a number of floors standing.

Then you'd expect wrong. You don't even have to be a demolitions expert to see how wrong that expectation is. It's comic book thinking. Expecting cohesion at real world scales one might get from a tinker toy.

When the structural supports gave and several tons of concrete and steel came down on the floors below the air between had to go somewhere. Thus, explosive venting. Not to mention the sound of the solid materials impacting. Thus the 'explosions' people heard.

As for the dust, controlled collapses pulverize concrete as well. Why shouldn't we expect an asymmetrical, uncontrolled collapse to be even messier?

 
At 28 March, 2007 17:30, Blogger derrickbennes said...

this site is such a joke, why is no one talking about all the thermite that was found in the base of the 2 buildings still burning even weeks after the towers fell? What about all the explosions in the building before it even collapsed? YOu guys arent dubunking anything. Youre not disproving the core facts of the whole thing. Jet fuel does not melt steel, a boeing 767 does not fit into a 16 foot hole, the lawn outside of the pentagon was completely unscathed, the was an exit whole in the other side of the walls. U guys are joke.

 

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