Sign up for free to keep watching this solution

Solution: Ted travels in a spaceship at 0.45 c relative to Alice, who'...

Question

Ted travels in a spaceship at 0.45 c relative to Alice, who's at rest on the Earth's surface. Ted travels for 20s, as measured on his watch. 

(a) Who measures the proper time, Ted or Alice?

(b) How much time elapses on Alice's watch during this motion?