An astronaut at rest on Earth has a heartbeat rate of 70 beats/min. What will this rate be when she is traveling in a spaceship at 0.

An astronaut at rest on Earth has a heartbeat rate of70 beats/min. What will this rate be when she is travelingin a spaceship at 0.90c as measured (a) by an observeralso in the ship and (b) by an observer at rest onthe Earth?