Centripetal Force and Acceleration

Centripetal Acceleration and Force We must understand the meaning of acceleration of moving bodies before trying to understand the centripetal acceleration. A body that moves equal distances in equal intervals of time in a specific direction has uniform or constant velocity and zero acceleration. The moving body has an acceleration when it either changes its direction of motion or the magnitude of the velocity or both. The rate of change of velocity is acceleration. Consider a body which is moving a circular path with uniform speed. We are actually considering the uniform speed to keep the discussion simple. Such a body is moving equal distances in equal intervals of time along the circular path. According our definition of acceleration this body must have an acceleration as it is continuously changing its direction of motion. The direction of motion of this body at any instant at a point on the circular path is along the tangent drawn at that point. Thus it can be noted that although the body does not change its magnitude of velocity it still has an acceleration due to change in direction of motion. This acceleration results due to a force, called centripetal force, that is acting on the body and is always directed towards the centre of the circular path. The acceleration of the body is directed towards the centre and therefore it is known as centripetal acceleration. Centripetal means centre seeking. Let us conclude by seeing an example. Consider a bucket full of water being whirled in a vertical circle with sufficient uniform speed. If the speed is not less than certain critical, the bulk of water stays in the circular path and does not spill even when the bucket is upside down at he highest point of the circular path. The bulk of water has a centripetal force acting on it. The force is provided by the reaction of the base of the bucket on the bulk of water.