Solve the all parts of following question:
Question: A 0.980 kg snowball is fired from a cliff 13.8 m high. The snowball's initial velocity is 16.2 m/s, directed 26.0° above the horizontal.
Part A: How much work is done on the snowball by the gravitational force during its flight to the flat ground below the cliff?
Part B: What is the change in the gravitational potential energy of the snowball-Earth system during the flight?
Part 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?
I need help to find how much work is done on the snowball by the gravitational force.