A particle moving with uniform speed in a circular path maintains:

In uniform circular motion (UCM):Speed is constant.Velocity ($\vec{v}$) is not constant because its direction changes continuously at every point on the circular path.Acceleration (${\vec{a}}_c$) is centripetal acceleration, which is directed towards the center. Its magnitude $v^2/R$ is constant, but its direction changes as the particle moves.Since both velocity and acceleration change their directions, they are considered "varying" vectors.