Work

Abstract

Up to now, you have learned to use Newton’s laws of motion to determine the motion of an object based on the forces acting on it. The methods you have learned are completely general and can always be applied to solve a problem. Unfortunately, in many cases we cannot find an exact solution to the equations of motion we get from Newton’s second law. Here we introduce a commonly used technique that allows us to find the velocity as a function of position without finding the position as a function of time—an alternate form of Newton’s second law. The method is based on a simple principle: Instead of solving the equations of motion directly, we integrate the equations of motion. Such a method is called an *integration method*. In this chapter, we introduce the work-energy theorem as a method to find the velocity as a function of position for an object even in cases when we cannot solve the equations of motion. This introduces us to the concept of work and kinetic energy—an energy related to the motion of an object. Finally we also address the rate of work done by a force—the power.