# physics

posted by
**Jamie** on
.

A 1.5 kg snowball is fired from a cliff 12.5m high with an inital velocity of 14 m/s directed 41 degrees above the horizontal.

a) how much work is done on the snowball by the gravitaitonal force during its flight to the flat ground below the cliff?

b) what is the change in the gracitational 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?

a) Is this the equation I would use: mgh= 1/2mv^2?

For b) and c) can you please explain to me how I would solve these problems?

Yes for a.

There is no change in total gpe. What work is done on the snowball by gravity to change its KE is equal.

c: if the top is zero, then the bottom is -h, and gpe is -mgh