In this chapter we continue the discussion of energy that we began. To do so, we define a second form of energy: potential energy U is energy that can be associated with the configuration (or arrangement) of a system of objects that exert forces on one another. If the configuration of the system changes, then the potential energy of the system can also change.
The idea of potential energy can be an enormously powerful tool in understanding situations involving the motion of an object. With it we can, in fact, easily solve problems that would require careful computer programming if we used only the ideas of earlier chapters.