If a 40 kg rock fell from a cliff and had a speed of 31.3 m/s when it hit the ground, what is it's kinetic energy?

Kinetic energy = (1/2) (mass) (speed) ²

It doesn't matter what direction the object is moving, what happened to set it in motion, or what route it's following.

Kinetic energy = (1/2) (40 kg) (31.3 m/s) ²

Kinetic energy = (20 kg) (979.69 m²/s²)

Kinetic energy = (20 x 979.69) (kg-m²/s²)

Kinetic energy = 19,594 joules