Answer: 7840 joules
Explanation:
Given that:
Potential energy of rock = ?
Mass of rock = 20 kg
Height = 40 metres
Acceleration due to gravity g = 9.8m/s2
Recall that potential energy (P.E) is the energy possessed by an object at rest. So, for the rock at rest:
P.E = Mass x Acceleration due to gravity x height
= 20 kg x 9.8m/s2 x 40 metres
= 7840 joules
Thus, the potential energy of the rock is
7840 joules
