Chapter 1, Problem 4P

An airplane flying upwind, downwind, and crosswind shows the main principle of the Michelson–Morley experiment. A plane capable of flying at speed c in still air is flying in a wind of speed v. Suppose the plane flies upwind a distance L and then returns downwind to its starting point. (a) Find the time needed to make the round-trip and compare it with the time to fly crosswind a distance L and return. Before calculating these times, sketch the two situations. (b) Compute the time difference for the two trips if L = 100 mi, c = 500 mi/h, and v = 100 mi/h.