Mechanical energy is the most familiar form of energy. It is the energy a substance or system has because of its motion. Every moving object has mechanical energy, whether it is a hammer driving a nail, a leaf falling from a tree, or a rocket flying in space. Mechanical energy pulls, pushes, twists, turns and throws.
Machines use mechanical energy to do work. Our bodies also use mechanical energy to perform motions such as throwing a ball or moving a pencil to write on paper.