An astronaut at rest on earth has a heartbeat rate of 61 beats/min. when the astronaut is traveling in a spaceship at 0.81c, what will this rate be as s measured by an observer also in the ship and an observer at rest on earth? (a) an observer also in the ship 0.5962 your response differs significantly from the correct answer. rework your solution from the beginning and check each step carefully. beats/min (b) an observer at rest on earth 61 your response differs from the correct answer by more than 10%. double check your calculations. beats/min