light trsavels at 3*10 m/s. an astrounaut shines a flash light in space. 4 hours later a martian sees a light from the astrounaut. how far away is mars from the astrounaut?
distance = speed * time
= 3*10^10 m/s * 4 hr * 3600s/hr = 4.32*10^14 m
= 3*10^10 m/s * 4 hr * 3600s/hr = 4.32*10^14 m