Acceleration to move in a circle
Physics Narrative for 11-14
The connection between circular motion and the motion of satellites
The centripetal force is interesting in that it acts at right angles to the direction of travel of the object moving along a circular path. As such, the centripetal force does not increase the speed of the object, but simply changes its direction of travel.
It's a bit strange (at least at first) to recognise that an object moving around a circular path at steady speed is accelerating. The centripetal force is an unbalanced force and as such accelerates the object. This acceleration is manifested as a continuous change in direction rather than as an increase in speed.
This is an acceleration because acceleration is defined as the change in velocity in each unit of time.
Velocity depends on both speed and direction, so a change in direction is enough to give a change in velocity.