Central Attraction

Central Attraction. When a body is moving under the action of a force which is continually directed towards a fixed point it is said to be subjected to a central attraction. If this is the only force-acting on it, the path described by the moving body is said to be a central orbit. Approximate examples occur in astronomy; the earth describes a central orbit round the sun, towards which it is continually being attracted by force of gravity. In a case like this the body moves in such a way that the line joining it to the centre of attraction sweeps out equal areas in equal times. This applied to planetary motion is one of Kepler's laws, determined by observation.