"In this chapter, the planar kinematics of a rigid body will be discussed. The study is important for the design of gears, cams, and mechanisms used for many mechanical operations. Furthermore, once the kinematics of a rigid body is throughly understood, then it will be possible to apply the equations of motion, which relate the forces on the body to the body's motion. When all the particles of a rigid body move along paths which are equidistant from a fixed plane, the body is said to undergo planar motion. There are three types of rigid body planar motion; in order of increasing complexity, they are: