) A 6.50 kg rock starting from rest free-falls through a distance of 30.0 m. a. Assuming no air resistance, find the amount of momentum that is transferred from the rock to earth as it collides with earth’s surface in a perfectly inelastic collision. b. What is the change in velocity of earth as a result of this momentum change? The earth’s mass is 5.972 x 10^24 kg. Show all your work, assuming the rock–earth system is closed.