"BDS" wrote in message
m...


"An airplane on a runway sits on a conveyer belt that moves in the
opposite direction at exactly the speed that the airplane is moving
forward. Does the airplane take off?" (Assuming the tires hold out, of
course.)

The plane cannot move forward - that means that it is standing still to
me.

BDS


You are taking the statement 'a conveyer belt that moves in the opposite
direction at exactly the speed that the airplane is moving
forward' to mean that somehow there is a force being applied to the mass of
the aircraft, equal and opposite the thrust generated by the propellor. The
only place the treadmill can exert any force an the airplane is the only
place the treadmill is touching the airplane: the wheels. Any motion of the
treadmill belt will be translated into rotation of the wheels. This will not
prevent the aircraft from moving forward, through the air and taking off.