Potential Energy

Potential energy is energy that is stored as a result of position or shape. The musician in Figure 3 adds energy to the cello string by plucking it. The energy is stored in the stretched string when the musician pulls it to one side. Then she releases the string and allows it to vibrate. The stored energy is converted into kinetic energy. You can also store energy just by picking up a book and holding it in the air. Let go of the book and that stored energy will turn into the kinetic energy of motion as the book falls to the floor. Plucking a string and lifting a book are two examples of stored energy—energy with the potential to do work. Two forms of potential energy are gravitational potential energy and elastic potential energy.

Figure 3 When this musician pulls the string of her cello to one side, the string is stretched and gains potential energy.

d