Simple hormonic motion is a kind of periodic motion bounded between two extreme points .

for example : oscillation of simple pendulum .

hopefully its helped u :)

-: If the acceleration of the vibrating body directly varies with the displacement of the body from the mean position and always directed to the mean position, the motion of that body is called simple harmonic motion.

Ex:- (i) The motion of a pendulum is an S.H.M.

(ii) The motion of vibrating mass attached to a spring is an S.H.M.