Which of the following statements is not correct about periodic and oscillatory motion?
All periodic motions can be called oscillatory motions.
Oscillatory motion: A to and fro or back and forth motion of a body about its mean position in a fixed interval of time. For example, the motion of a pendulum.
Periodic motion: Any motion that repeats itself at regular interval of time. For example, the motion of planets around the Sun, the motion of a pendulum.
All oscillatory motions are periodic but NOT all periodic motions are oscillatory. For example, the motion of a planet around the Sun is periodic but not oscillatory.