Uniform circular motion, motion of a particle moving at a constant speed on a circle. In the Figure, the velocity vector v of the particle is constant in magnitude, but it changes in direction by an amount Δv while the particle moves from position B to position C, and the radius R of the circle sweeps out the angle ΔΘ.
In a uniform circular motion (UCM), a particle takes the same time to complete each revolution, a distance equal to the circumference of the circle. Therefore, a UCM is called a periodic motion.
