For a particle in uniform circular motion, the direction of its velocity changes continuously but the magnitude remains constant. For this, a force must act along the radius, towards the centre of the circle, to maintain the circular path. Hence, there is acceleration acting on the body towards the centre of the circle.
Thus, for a particle executing uniform circular motion, there must always be acceleration directed towards the centre of the circular path along the radius. This acceleration is called normal acceleration and the force responsible for this acceleration is known as centripetal force.
When a particle is moving along a circular path, the particle is accelerated towards the centre of the circular path in a direction normal to the direction of its motion. This acceleration of the particle is known as normal acceleration.