All that one needs to know, to be able to conclusively prove that the Twin Towers were demolished, is that the towers fell in roughly 10 seconds, that is, that they fell at about the same rate that an object falls through air. The observed collapse of the World Trade Centers 1 and 2 have been measured at near the rate of free fall. This is the rate at which nearly ALL of the "falling energy" (kinetic energy from gravity) must deliver the building to ground level ASAP. This leaves NO energy for smashing and pulverizing the concrete slabs NOR for shredding construction steel. Can't have it both ways! There is only so much kinetic energy available and it can either be used for shredding steel and pulverizing concrete OR it can be used for acceleration toward the ground. The building simply can't get to the ground in the requisite time that is observed unless most of the energy goes into acceleration. There is no room for a significant quantity of the potential energy being utilized in any other way than falling or the building does NOT get to the ground in time. It's a race, you see. A race against the clock.
Free fall is the unrestricted acceleration from a height toward an impact with the Earth. The WTC towers both fell to the Earth very quickly as is timed by seismographs and video. They fell at the rate of free fall; that is, they fell as though NOTHING was in their way. The speed at which they fell totally cancels the theory that they "pancaked" one on top of the other and then stressed one floor after another until the entire mass was in rubble on the ground. According to rate of collapse, the towers fell smoothly and without encountering obstruction or resistance of any kind. That's it! It's impossible for the floors to fall / crash / fall / crash / fall...and get to the ground level in 10 seconds. Starting from the 80th floor, for example, at just ONE second per floor, it would take 80 seconds to fall--eight times too long. Even at only 1/2 second per floor it is STILL four times to slow. The only way that the WTC towers could get to the ground within approximately ten seconds is to encounter a weakened building on the way down--demolition.
The floors themselves are quite robust. Each one is 39" thick; the top 4" is a poured concrete slab with interlocking vertical steel trusses (or spandrel members) underneath. This steel would absorb a lot of kinetic energy by crumpling as one floor fell onto another, at most pulverizing a small amount of concrete where the narrow edges of the trusses strike the floor below. And yet we see a very fine dust being blown very energetically out to the sides as if the entire mass of concrete (about 400,000 cubic yards for the whole building) were being converted to dust. Remember too that the tower fell at almost the speed of a gravitational free-fall, meaning that little energy was expended doing anything other than accelerating the floor slabs.
Considering the amount of concrete in a single floor (~1 acre x 4") and the chemical bond energy to be overcome in order to reduce it to a fine powder, it appears that a very large energy input would be needed. The only source for this, excluding for now external inputs or explosives, is the gravitational potential energy of the building. Any extraction of this energy for the disaggregation of the concrete would decrease the amount available for conversion to kinetic energy, slowing the speed of the falls. Yet we know that the buildings actually fell in about 9 seconds, only slightly less than an unimpeded free-fall from the same height. This means that very little of the gravitational energy can have gone toward pulverizing the concrete. http://911research.wtc7.net/wtc/analysis/collapses/concrete.html
There is no wiggle room on the laws of physics. For the towers to fall at that rate there had to be NO resistance from each of the floors encountered on the way to the ground.
Anyone with a little common sense will realize that the top of a building does not cannot pass through a structure made of concrete and steel at the same rate as it falls through air. This just doesn't happen, unless, of course, the lower part of the building has lost its structural integrity (and this is usually due to the detonation of a multitude of small explosive charges as seen in controlled demolitions).
The fact that the towers collapsed in about 10 seconds is clear evidence that the upper portion of each of the towers passed through the lower portion at about the same rate that it would have fallen through air. The fact that the towers fell this quickly (essentially at the rate of free-fall) is conclusive evidence that they were deliberately demolished.
Believing that there is nothing wrong with the towers collapsing so quickly, is roughly analogous to believing that people pass through closed doors as quickly as they pass through open doors. [Something in the way delays the passage.]
The fact that they fell at such a rate means that they encountered essentially no resistance from the supposedly undamaged parts of the structure. That is, no resistance was encountered from any of the immensely strong parts of the structure that had held the building up for the last 30 years. From this one can conclude that the lower undamaged parts were actually very damaged (probably by the detonation of a multitude of small explosive charges as is usual in a controlled demolition). http://guardian.150m.com/wtc/proof.htm
Some people trying to use "common sense" without a knowledge of the laws of physics suppose that the addition of one floor after another would make the towers fall faster and faster. An elementary principle of masses falling through space was demonstrated at the Leaning Tower of Pisa nearly 500 years ago. The larger mass does NOT accelerate through space faster than a lighter, more dense mass. It will, however, cause the shredding force because of the connection between the slab and the outer wall.
It is not even necessary to disprove all of the allegations in the official conspiracy theory. All that is necessary is to disprove ONE allegation to demonstrate the whole to be a lie.
* All that is needed is the difference between an unobstructed free
fall and an obstructed free fall.
* All that is needed is the research of Dr. Kee Dewdney and his associates on the functionality of cellphones at altitude and velocity to dismiss not only the allegations of cellphone communications in aircraft but the entire fabric of lies offered by the US Government.
* All that is needed is the absence of any explanation for the penetration through A, B, C, D, and E rings at the Pentagon leaving a circular path and no debris in the courtyard that could have caused the hole....except for Broach technology.
Any one of these among many others is all that is required to prove the lie of the official conspiracy theory. All of this has been studied and discussed, argued and reargued ever since it happened by folks with degrees in engineering and physics. It's been examined and re-examined by thousands of qualified scientists who have studied long hours to come to understand what really happened.
Click here for a dialogue with Mr. Sheeple about the Fall of the WTC
So you're suggesting a la Eagar that floors fell on each other from the top down, the weight of the floors above exceeding the maximum load of the floor on which they fell accumulating more mass and more readily destroying the structure in each successive floor. How long would you estimate it would take for your scenarios of fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash-fall-smash to be complete?
Would you propose something like one second for each floor? Perhaps we could cut that in half, say one half second each floor, taking a bit more time at the top and a bit less at the bottom. How many seconds is that? Let's see now....about 110 floors. Let's knock that down to 100 floors even. That would be.....50 seconds. Nope, won't work. Five times too long. That's way too long.
Then let's say that it took only a half-second on the top 50 floors and a quarter of a second in the bottom 50 floors. That would be 25 seconds for the top 50 floors to get half way down...added to 12.5 seconds for the WTC to fall the rest of the way. That's 37.5 seconds. Nope. That won't work. That's nearly 4 times too long.
So what if it only took half second to smash-fall the top 25 floors, one quarter second to crush each of the next 25 floors, one tenth of a second to demolish the next 50 floors......that's 12.5 + 6.25 + 5 = 23.75 seconds. Nope! Still took too long by more than double.
C'mon! I'm squeezing this hypothesis as much as I can and it still seems way off. (How fast can you say fall-smash 100 times? Try it. Time it.) OK. Let's try a quarter of a second in the top 50 and one tenth the rest of the way. That's 12.5 + 5 = 17.5 seconds. Still too slow.
OK. That's it! For anything to be so ground up as the WTC ended up, lot's of powder. stuff has to be hitting other stuff, right. So there HAS to be SOME collision time to do all that work. We saw the pieces, the dust AT THE START of the fall. Demolition does take energy and in this case a lot of energy. That energy of smashing + the energy of falling (yes, even falling, acceleration) must all be accounted for.
Calculations for the FASTEST time that the WTC could reach the bottom is about 10 seconds. That's with NOTHING getting in the way, not even touching anything else on the way down. It's called free fall. Free fall represents the sole effect of gravity causing a mass to accelerate through space between a point above the earth to the surface of the earth.
The hypothesis you have suggested and that Professor Eagar and the Bush Liars' Club would have us believe is that a 110 story building fell from 1300 feet up to approximately street level at the rate of free fall yet it serially crushed floors below on the way down as though they weren't there. According to the Official Conspiracy Theory, WTC was in a hurry that cannot be accounted for by laws of physics. You can't have the WTC fall at the rate of free fall and still encounter even the tiniest bit of resistance on the way down. A tiny bit of resistance on the way down means that it can't get there in the time that is in evidence. Eagar's hypothesis fails simply the top can't get down as fast as the documented facts demonstrate. If it doesn't fit the facfs, it's filed in the circular file.
It's not about "wanting" to believe. The hypothesis proffered by the Prof. just simply does NOT fit the observed facts. If you wish to throw out the observed and provable facts, then any opinion will do. But al-Qaeda could not repeal the laws of physics even if they COULD get the USAF to stay on the ground for an hour while they flew all over, the Northeast, (even over several USAFB). Unless, of course, Allah is really that good.
There you have a choice:
1. Allah is all powerful and answers the prayers of his people
2. The Bush Liars' Club got started earlier than most people figured.
http://www.the7thfire.com/Politics and History/law_of_free_fall.htm