Answer: If a 21.0 kg rock rests on the edge of a cliff 32.0 m high, the gravitational potential energy gained by the rock would be 6585.6 Joules.
Explanation:
Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.
As given in the problem a 21.0 kg rock rests on the edge of a cliff 32.0 m high, then we have to calculate the potential energy gained by the rock,
The potential energy of the rock = 21 × 9.8 × 32
= 6585.6 Joules.
Thus ,If a 21.0 kg rock rests on the edge of a cliff 32.0 m high, the gravitational potential energy gained by the rock would be 6585.6 Joules.
Hope this helps.