Question

1)A toy train is initially at rest on a track fastened to a bicycle wheel, which is free to rotate. How does the wheel respond when the train moves clockwise? When the train backs up? Does the angular momentum of the wheel-train system change during these maneuvers? How would the resulting motions depend on the relative masses of the wheel and train?

Answer 1

The train and the tire move in opposite directions. The angular momentum stays the same IF the tire axle is frictionless. That is probably what they want ou to assume. The larger the (wheel/tire) mass ratio, the lower the (wheel/tire velocity ratio, because the
(MV)train = (MV)tire

Answer 2

counterclockwise, clockwise, no