A muon is created 60 km above the surface of the earth. In the earth’s frame, the muon is traveling directly downward at 0.9999c.

a. In the earth’s frame of reference, how much time elapses between the muon’s creation and the time it reaches the surface?

b. Use time dilation to determine, in the muon’s frame, how much time elapses between the muon’s creation and the time it reaches the surface.

c. In the muon’s frame of reference, length contraction reduces the distance between the point at which it is created and the surface of the earth. What is this distance?

d. The ratio of the distance you calculated in part c and the time you calculated in part b is a speed. Calculate this speed; what do you notice?