4. Superman, who has a mass of 107 kilograms and a height of 1.91 meters, has been flying through space at a speed of 200 000 kilometers per second for 3 years relative to a stationary observer on Earth. Using 300 000 kilometers per second as the speed of light: him is

a.)how much time has passed through him?

b.)how much height has he lost while flying?

c.)how much mass has he gained while flying?​