ABSTRACT
Circular motion is everywhere, from atoms to galaxies, from flagella of bacteria to Ferris wheels. Gravity plays a major role in determining the motions of the planets, since it supplies the force necessary to maintain their orbits. The description of circular motion in angular form is analogous to the description of linear motion. A simple but important type of circular motion is uniform circular motion, which occurs when an object moves at a constant speed in a circular path. The acceleration of uniform circular motion is not in the same direction as the instantaneous velocity. The speed of an object in uniform circular motion is constant, but the object's velocity changes in the direction of motion. The velocity vector of an object in uniform circular motion is constantly changing direction. The centripetal force, like the centripetal acceleration, is directed radially toward the center of the circular path.
