Originally posted by rush969
But he is wrong when he makes a point of the toppling part having to continue toppling. This is actually not possible on such a structure, gravity
takes over and it comes down instead of keeping moving to the side.
In physics, gravity causes the movement either way. If it starts leaning outward about a fulcrum, that's still caused by gravity, and it's still
momentum, and it still has to be conserved unless balanced by equal and opposite force. It doesn't have to drop straight down to be falling because
of gravity, and in fact falling straight down makes the least sense because thermodynamically that is the path of the absolute most resistance and it
would require unbelievable luck for the collapse to have been symmetrical enough to prevent it from lop-siding for that reason. It would constantly
be "trying" to tip over to find a quicker way to the ground.
But you know this is all just hypothetical, because really the towers didn't just fall down at all. They were being blown out in all directions the
whole way down, so that when it was all said and done there wasn't any debris in either footprint reaching higher than the lobby, and the lobby
itself was still intact. At the same time about 90% of the masses of both towers is laying all around the complex. Imagine how much energy that would
have taken out of the collapse, to throw all of that outwards, and how much mass would no longer be available to fall into what was left.
There´s no hinge on which this portion of building would be supported, and it´s not constructed to remain in one piece and be inclined for
any degree without suffering failure.
If you mean the leaning had no fulcrum, you're obviously wrong. It could never have leaned out like that in the first place if it didn't. And
you're right, it would have "suffered failure," but that also means conserving momentum. That doesn't mean the momentum just goes away. In fact,
the momentum is what "pulls" on the connections and causes failures in the first place.