Dear Vinod, have you ever seen a pendulum clock? The vintage ones? The leader or the pendulum bob is the perfect example of Oscillation motion. The pendulum bob repeatedly moves to the right and to the left from the center. It goes to the extreme left and comes back to the center and goes to the extreme right. This is called the Oscillary motion. It can be defined as "The repeated motion in which an object repeats the same movement over and over".

Periodic motion can be best explained by a rocking chair example. The rocking chair moves in a certain intervals of time. Let's say if you are sitting in a chair, there is a certain time interval between each swings. This is called periodic motion. This can be defined as "A motion repeated in equal periods of time". In a way, oscillatory motion is a periodic motion.

• Every oscillatory motion is a periodic motion.
  
• Not necessarily a periodic motion is oscillatory.
  

Hello there!

Greetings!

Periodic motion is the motion that repeats itself after fixed intervals of time. This fixed interval of time is known as time period of the periodic motion. Examples of periodic motion are motion of hands of the clock, motion of planets around the sun etc. Oscillatory motion is to and fro motion of an object from its mean position . Examples of oscillatory motion includes Oscillation of simple pendulum, Vibrating strings of musical instruments is a mechanical example of oscillatory motion, Movement of spring, Alternating current is an electrical example of oscillatory motion.  Actually, Oscillatory motion is a type of periodic motion.

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