Define Oscillatory Motion.

The to and fro motion of a body about a fixed point is called oscillatory or periodic motion. In this motion, the body repeats itself on the same path. If there is no friction the body continues its movement forever. There are two types of oscillations: linear oscillation and circular oscillation.

Examples of linear oscillation
1) Oscillation of floating cylinder.
2) Oscillation of strings of musical instruments.

Examples of circular oscillation
1) Movement of the earth around the sun.
2) Oscillation of simple pendulam