A rotating force pushing inwards

For a body to move in a circle there must be a force on it directed towards the centre. This is called the centripetal force and is necessary to produce continuous change of direction in a circular motion. The centripetal force is also known as 'centre seeking' force. In case of the moon, gravitational force between moon and earth acts as the centripetal force. When a stone tied at one end of a string is whirled in a circle, the pull in the string provides the centripetal force.

The magnitude of the centripetal force, Fc, required causing an object of mass m and speed v to travel in a circular path of radius r is given by the relation

Fc = mv2 / r

The magnitude of the centripetal force, Fc, required causing an object of mass m and speed v to travel in a circular path of radius r is given by the relation

Fc = mv2 / r