Quote:
Originally Posted by **********
Actually Greg you are making a wild assumption here. What would need to do is determine the terminal velocity of the building as it fell. Terminal Velocity is the downward force of gravity minus the upward force of drag. As each piece of the building gets stuck to the downward falling piece it will gain momentum until the amount of drag it hits on the way down stops the acceleration. This momentum is the limiting value of the acceleration process, since the effective forces on the body more and more closely balance each other as the terminal velocity is approached. And since there is more floors above crashing each floor below, terminal velocity is never reached until it hits the ground. Thats why everything including the ground floors are utterly destroyed.
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Ah you and your terminology.
Fine.
The assumption is not "wild" as you define it. And you're using "terminal velocity" as if the top part of the building was dropped from tens of thousands of feet above the remainder of the reportedly structurally sound four-fifths of the building. It wasn't.
Terminal velocity? OK. So one-fifth of the building (the top) lost support and began to cave. The other four-fifths evaporated under it's weight? Of course not.
If this was the case, then the bottom four-fifths of the structure should have stopped or slowed the top part's downward motion. Simple Newtonian law, here.
Terminal velocity is the action of one mass resisting to the force or velocity of another mass. Seeing as their was no velocity involved, the path of least resistance should have determined that the collapse would have stopped right there, or toppled into Manhattan and killed thousands more.