Oscillatory Motion

What is Oscillatory Motion?

Oscillatory motion is defined as the to and fro motion of an object from its mean position. The ideal condition is that the object can be in oscillatory motion forever in the absence of friction but in the real world, this is not possible and the object has to settle into equilibrium.

To describe mechanical oscillation, the term vibration is used which is found in a swinging pendulum. Likewise, the beating of the human heart is an example of oscillation in dynamic systems.

Examples of Oscillatory Motion

Following are the examples of oscillatory motion:

  • 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
  • Series of oscillations are seen in cosmological model

Simple Harmonic Motion

Simple harmonic motion (SHM) is a type of oscillatory motion which is defined for the particle moving along the straight line with an acceleration which is moving towards a fixed point on the line such that the magnitude is proportional to the distance from the fixed point.

For any simple mechanical harmonic system (system of the weight hung by the spring to the wall) that is displaced from its equilibrium position, a restoring force which obeys the Hooke’s law is required to restore the system back to equilibrium. Following is the mathematical representation of restoring force:



  • F is the restoring elastic force exerted by the spring (N)
  • k is the spring constant (Nm-1)
  • x is the displacement from equilibrium position (m)

Difference between Oscillatory Motion and Periodic Motion

Periodic motion is defined as 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 defined as the to and fro motion of the body about its fixed position. Oscillatory motion is a type of periodic motion. Examples of oscillatory motion are vibrating strings, swinging of the swing etc.


  1. motion of eatrh arround the sun is it oscillatory motion or shm

    1. The motion of the Earth around the sun is neither an oscillatory motion nor a simple harmonic motion as the motion is not a to and fro motion about a mean position.

      1. motion of Earth around the sun is periodic motion.

    2. The motion of the earth around the sun is an example of planetary motion. Also, there are three laws associated with the planetary motion and these laws are known as Kepler’s laws.

  2. Your teaching is very beautiful and understanding

  3. Very nice explain

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