Periodic motion means that the motion repeats after a finite amount of time. So, if you wait for some time, the system return to the same position. The amount of time required to return to the same position is a constant.
Which of the following is not an example of periodic motion?
  • A planet orbiting the Sun in a circular orbit
  • The ticking of the pendulum in a grandfather clock
  • A factory manufacturing a product on an assembly line
  • A ball bouncing on the floor after unequal intervals of time