Physics · Oscillations · NEET
Yes. Oscillatory motion always repeats its to-and-fro path after a fixed time, so it must be periodic. A swinging pendulum returns to the same point after each period T, so it is both oscillatory and periodic.
No. This is the key point. A motion can repeat after fixed time without going to-and-fro about a mean position. Example: the Earth going around the Sun repeats every 365 days (periodic) but it never moves back and forth about a fixed point, so it is not oscillatory.
Uniform circular motion, like the hands of a clock or a planet orbiting the Sun. The motion repeats after a fixed period, but there is no restoring force pulling it back and forth about a mean position, so it is periodic only, not oscillatory.
An oscillatory motion needs a mean (equilibrium) position and a restoring force. When the body is displaced from the mean position, this force always tries to bring it back, so it moves to and fro. Circular or orbital motion lacks this back-and-forth restoring behaviour.
Simple Harmonic Motion is both. SHM is a special oscillatory motion where the restoring force is directly proportional to displacement (F = -kx). Since it is oscillatory, it is automatically periodic too.
They are almost the same idea. Vibratory motion is just oscillatory motion with a very small amplitude and high frequency, like a plucked guitar string or a tuning fork. Both are to-and-fro about a mean position.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Periodic motion only needs to repeat after a fixed time. Oscillatory motion must also be a to-and-fro motion about a mean position with a restoring force. So oscillatory is a special case of periodic.
In physics they mean the same to-and-fro motion. By habit, we call low-frequency to-and-fro motion oscillation (a pendulum) and high-frequency small-amplitude motion vibration (a tuning fork).
No. It is periodic because it repeats after a fixed time, but there is no to-and-fro motion about a mean position, so it is not oscillatory.
It repeats its motion after a fixed period T (periodic) and it moves to and fro about its lowest mean position under a restoring force (oscillatory), so it satisfies both definitions.
No. All SHM is oscillatory, but oscillatory motion is SHM only when the restoring force is directly proportional to displacement. A large-amplitude pendulum is oscillatory but not exactly SHM.
