[h=2]Free Fall[/h] According to Roedy Green's
How You Know 9-11 Was an Inside Job:
All three World Trade Towers fell faster over the first half of the collapse than physics allows by free fall. That meant they had to have an assist, e.g. an explosive push from pre-planted demolition charges, not just gravity pulling them down. The maximum collapse for free fall is computed by distance = g t
where g is the acceleration due to gravity 32 feet per second per second, and t is time in seconds. In other words, free fall collapse should start out slowly and accelerate faster and faster for the big finale.
This is just plain weird. Whether a building falls by deliberate demolition or catastrophic failure, the collapse will be governed by gravity. Even if you used a teleporter to magically make several stories vanish, the part above would only fall as fast as gravity would accelerate it. Only if there was some kind of thruster pushing the building
down could it fall faster. Why install a useless Rube Goldberg device? Once the building begins to collapse, who needs anything to accelerate it? Gravity has a pretty reliable record of pulling things down. And where's the evidence for faster than free fall collapse?
The videos show that the towers took 15 seconds to collapse. The free-fall time for something to fall 400 meters is about 9 seconds. So, no, the towers did
not fall faster than free fall.
911Research claims:
This rate is still much too fast to be explained by a gravity-driven collapse given that the descending rubble would have to crush and accelerate almost 1000 feet of vertical intact structure. It is especially revealing that each tower disappeared at about the same rate as the rubble fell through the air, as if the tower's structure provided no more resistance to the descent of rubble than did air.
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| All photos of the collapse show a plume of debris extending far below the main level of collapse. So the debris did fall appreciably faster than the building itself. The building provided little more resistance than air for the simple reason that a skyscraper is mostly air.In the photo at left the collapse is about where the cloud fills the entire width of the picture, but the debris in free fall has almost reached the ground.
Note that the debris is at least a building width beyond the building itself. No competent controlled demolition flings debris that far.
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The fall doesn't have to
crush the stories beneath. It merely has to stress the structural elements until the fasteners pop and the welds break. The impact of that pancaking material will cause the outer vertical members to bow outward, then fly outward violently when failure occurs. There's no need to appeal to explosives to fling material outward from the buildings.
If a story is 4 meters high, it will take an object about 0.9 seconds to fall one story, by which time it will be going 9 m/sec. So once the collapse starts, the overlying structure will be falling at 9 m/sec by the time it has fallen one story. If we crush the collapsing story into rubble half a meter thick and expect the collapse to stop at that point, what kinds of forces are involved? We go from 9 m/sec to zero in half a meter, or 1/18 of a second. However, during that deceleration the velocity is decreasing, and the average velocity turns out to be half of the initial velocity, so the crunch time is 1/9 second. So the acceleration is -9 m/sec divided by 1/9 sec = -81 m/sec[SUP]2[/SUP], or about 8 g's.
This is the difference between a
static load and a
dynamic load. In the north tower, with about ten stories above the impact, the dynamic load was about equivalent not to ten stories but to
eighty, nearly the total height of the building. I doubt if the tower at that level was engineered to support eighty stories - why waste the steel? Actually the loads are much greater because the initial collapse involved a fall of about three or four stories, not just one, and the dynamic loads on the points that actually resist the fall - the welds and the rivets, will be far greater. If you try to stop the collapse in the millimeter or so a rivet or weld can deform before failing, you're talking
hundreds of g's. In the south tower, where the top 25 or so stories fell, the impact load at eight g's would be equivalent to 200 stories, or
twice the total height of the building. Some conspiracy buffs argue that engineering standards require a safety factor several times the actual load on the structure, but the dynamic loads would far overwhelm those standards.
This, by the way, is the reason controlled demolition works at all. If physics worked the way 9-11 conspiracy buffs think, once you blew the lower stories of a building, the upper part would just drop and remain intact. Of course it doesn't because once the building begins to fall, the dynamic loads are far beyond the static strength of the building.
911Research devotes a lot of effort to debunking what it regards as disinformation campaigns designed to deflect attention from the theory of controlled demolition. But we keep coming back to the fundamental issue how any building can fall
faster than gravity or why a conspirator would feel the need to set up a mechanism to do something so useless.
