Uniform circular motion describes the motion of the body travelling in a circular path at constant speed. Though the speed is constant, the velocity is not; velocity is a vector quanity that depends on both magnitude and direction. The direction of the velocity vector is continuously changing while travelling in a uniform circular motion. This changing velocity indicates the presence of acceleration. This centripetal acceleration is of constant magnitude and directed at all times towards the axis of rotation. Thus, the angular acceleration remains constant in a uniform circular motion.