What's the process?

A 5-kg rock is dropped over the edge of a 15m cliff. What is the momentum of the rock as it strikes the ground?

Falling objects form an interesting class of motion problems. For example, we can estimate the depth of a vertical mine shaft by dropping a rock into it and listening for the rock to hit the bottom. By applying the kinematics developed so far to falling objects, we can examine some interesting situations and learn much about gravity in the process.