A 0.21-kg apple falls from a tree to the ground, 4.0 m below. Ignoring air resistance, determine

Question:

A 0.21-kg apple falls from a tree to the ground, 4.0 m below. Ignoring air resistance, determine the apple's kinetic energy, K, the gravitational potential energy of the system, U, and the total mechanical energy of the system, E, when the apple's height above the ground is

(a) 4.0 m,

(b) 3.0 m,

(e) 0 m. Take ground level to be y = 0.