Skip to content

Centripetal Force

Applying Newton's second law F = ma to the centripetal acceleration gives F = mv2/rSince v = r ω , the centripetal force

F = mω2r.

According to Newtons second law, the centripetal force is proportional to the centripetal acceleration and takes place in the same direction i.e. towards the centre of the circle.Note that the object does not travel in the direction of the force. The centripetal force is perpendicular to the direction of motion so as there is no component of the force in the direction of motion there is no work done on the object by the centripetal force. Since no work is done, the object does not gain kinetic energy and maintains a constant speed.

Read the text

Read the text and highlight anything you think is important. When you go on, the text is hidden and you answer from memory.

Specification: AQA Physics (7408), A-level, 3.6.1.1 Circular motion. Topic: Circular Motion.

Key terms in this lesson

Centripetal acceleration
The acceleration of an object moving in a circle at constant speed, directed towards the centre of the circle, equal to v squared over r.

More in Circular Motion

All 9 lessons in Circular Motion · All AQA A-level Physics topics