Question

Which one of the following is not an example of periodic motion?

• A. Heartbeat of a healthy person
• B. The motion of a pendulum
• C. Apple falling from a tree
• D. Moon’s motion around the earth

Answer 1

The correct option is C Apple falling from a tree

Motion which repeats itself after a regular interval of time is called periodic motion.

The beating of the heart of a healthy person is periodic in nature as it repeats after a fixed interval of time. Similarly, the motion of a pendulum and the moon’s motion around the earth are also periodic in nature.

But once an apple falls off a tree, it stays on the ground. Since the motion is not repeated, therefore it is not periodic in nature.
The motion of an apple falling from a tree is an example of the rectilinear motion as it falls vertically down due to gravity.