Plane on conveyor... Will it ever take off?

[fasternyou929]

Originally Posted by Avatard

There's one other factor [er, two].

Because the plane (due to its being essentially temporarily "immobilized" on a treadmill) is not really moving against the ambient air (well, no more air than the thrusters will provide in airflow); the plane is essentially taking off with a matching tailwind, as the ambient air is not aided in differential movement across the plane by any takeoff-speed-provided airflow.

I thought that was the point of the riddle, that the conveyor cannot immobilize the plane since the plane propels itself using air, not the wheels. So if the thrusters are set for 240mph and the treadmill is set for 240mph in the other direction, the plane still moves at 240mph but the wheels spin freely against the conveyor at 480mph. Or no?