9-11 & the Laws of Physics

I recently watched a web documentary focused on the collapse of the twin towers.  It questioned the near free-fall collapse of the buildings, specifically, how it could be explained applying the laws of physics.

A billiard ball dropped from the top of the Trade Centers would have taken just under 10 seconds to hit the ground.  The towers fell in under 10 seconds, basically free-fall speed.  Even if the buildings pancaked, physics would dictate resistance from lower floors significantly slowing the rate of collapse.