Question

define simple harmonic motion

Answer 1

A body is said to be having simple harmonic motion if it has,
1. to and fro motion about a fixed point
2. Acceleration is directly proportional to displacement
3. Direction of acceleration is opposite to the direction of displacement.
Example : Pendulum

Answer 2

When a body oscillates about its mean position in a plane then that motion is called simple harmonic motion.
Example: Pendulum- the bob of the pendulum oscillates about its mean position.