Centripetal acceleration is the acceleration directed towards the centre of curvature of the path of a body which is moving along that path with a constant speed.
Mathematically,
Centripetal acceleration = (Velocity)2 / radius.
Dimensional Formula of Velocity = M0L1T-1
Dimensional Formula of Radius = M0L1T0
Putting these values in above equation we get,
Dimensional Formula of Centripetal acceleration = M0L1T-2
SI unit of Centripetal acceleration is ms-2