An asteroid is hurtling towards earth at 1800 m/s. It has a mass of 500 kg. Superman has to stop the asteroid so it doesn't destroy the earth. How fast must Superman, who has a mass of 100 kg, fly at the asteroid in order to push it away from the earth at a speed of 25 m/s (he will travel with the asteroid out of earth's atmosphere)? Is this collision elastic, inelastic, or perfectly inelastic? Explain your answer and show all steps