What is oscillatory motion? Give its examples.

(N/A) If a body moves to and fro,back and forth,or up and down about a fixed point in a definite interval of time,such a motion is called an oscillatory motion.
For example:
$(1)$ $A$ ball placed in a bowl will be in equilibrium at the bottom. If displaced a little from this point,it will perform oscillations in the bowl.
$(2)$ The motion of the pendulum of a wall clock is an oscillatory motion.
$(3)$ The motion of a loaded spring,when the load attached to the spring is pulled once a little from its mean position and released.
Every oscillatory motion is periodic,but every periodic motion need not be oscillatory.
Restoring force is produced in such type of motion; hence,no external force is constantly needed for the continuation of this motion. Such type of motion is also known as harmonic motion.