a. the pilot of the spaceship measures the length of the moving ship as 20 meters. determine its length as measured by a person on earth
b. the pilot of the spaceship observes that the spaceship travels for 5 years. determine how much time has passed according to a person on earth.
c. some time after passing the earth, the pilot shoots a laser pulse backward at a speed of 2x10^8 meters per second with respect to the spaceship. determine the speed of the laser pulse as measured by a person on earth