<Dl> <Dd> a = r α, (\ displaystyle a = r \ alpha, \!) </Dd> </Dl> <Dd> a = r α, (\ displaystyle a = r \ alpha, \!) </Dd> <P> where r is the radius or distance from the axis of rotation . This is also the tangential component of acceleration: it is tangential to the direction of motion of the point . If this component is 0, the motion is uniform circular motion, and the velocity changes in direction only . </P> <P> The radial acceleration (perpendicular to direction of motion) is given by </P>

The force that keeps objects moving in a circle is called centrifugal force