Question

every oscillatory motion is periodic but every perioodic motion is not oscillatory . justify

Answer 1

Hey,

I think it's because oscillatory motion is repetition of the same movement at equal intervals however, not each periodic motion is repetition of the same movement, for example, a complete orbit in 365 days is periodic but not oscillatory.

Tried my best to justify.

Answer 2

yaaa
The word oscillatory refers to something that moves back and forth repeatedly. The word periodic refers to something that repeats after a regular amount of time. the motion of planets around the Sun is always periodic but not oscillatory. The motion of the pendulum of a clock is periodic as well as oscillatory.
hope it helps you