Cams are mechanical devices used to convert rotational motion into linear motion. They consist of a rotating element with a specific shape, which pushes against a follower. This follower moves in a predetermined path based on the cam's design, making cams essential in various machines, such as engines and automated systems. There are different types of cams, including circular cams, sliding cams, and camshafts. Each type serves specific functions in machinery. For example, camshafts are crucial in internal combustion engines, controlling the timing of valve openings and closings to optimize engine performance.