일반물리학 1 — Potential Energy and Conservation of Energy: Problem 8

8 A 1.50 kg snowball is fired from a cliff 11.5 m high. The snowball’s initial velocity is 16.0 m/s, directed 41.0° above the horizontal. (a) How much work is done on the snowball by the gravitational force during its flight to the flat ground below the cliff? (b) What is the change in the gravitational potential energy of the snowball–Earth system during the flight? (c) If that gravitational potential energy is taken to be zero at the height of the cliff, what is its value when the snowball reaches the ground?