A 7.40 lb rock sits on top of a 76.0 foot cliff. it is pushed off. What is the energy in Joules of the rock just before it hits the ground?

If you want it in Joules, use SI units for mass, g and height H.

E= M g H is the kinetic energy just before it hits the ground

M = 3.36 kg
g = 9.8 m/s^2
H = 23.17 meters