View Single Post
  #40  
Old 03-07-2006, 06:57 AM
wildwriter wildwriter is offline
Guest
 
Join Date: Mar 2006
Location: New Jersey
Posts: 10
[QUOTE=VicSarjoo]The treadmill is irrelevant because it doesn't matter whether the plane is on it's wheels, or suspended from above by a set of steel chains hanging from a curtain rod that runs the length of the runway.

No, this is NOT AT ALL like this sort of situation. To create the situation of your "set of steel chains" the plan has to move through the air, to create the lift. Until the plane reaches a speed relative to the air mass around it (or, equivalently, to a stationary observer also not being moved by the treadmill) the wheels sit on the conveyor belt and tend to get moved backward alolng with the surface of the conveyor belt.

This is not a force-vector calculation (except ina VERY abstract way) and it is not a closed-vs-open environment. It is a semantic/logic exercise and subject to the same problems of any other logic problem. The key difficulty is sometimes called "assumptions contrary to fact" wherein we have put forth assumptions (that it is possible to build a conveyor belt that can move at a speed opposite to (and synchronize with) a forward motion of a plane) that are contrary to fact.