A motion, which repeat itself over and over again after a regular interval of time is called a periodic motion and the fixed interval of time after which the motion is repeated is called period of the motion.

Examples :

(i) Revolution of earth around the sun (period one year)

(ii) Rotation of earth about its polar axis (period one day)

(iii) Motion of hour’s hand of a clock (period 12-hour)

(iv) Motion of minute’s hand of a clock (period 1-hour)

(v) Motion of second’s hand of a clock (period 1-minute)

(vi) Motion of moon around the earth (period 27.3 days)