14.2 Simple Harmonic Motion

14.2 Simple Harmonic Motion

Simple harmonic motion is a type of oscillation or vibratory motion produced under the action of restoring force.

The necessary conditions for the execution of simple harmonic motion are:

• The restoring force shall be directly proportional to the displacement from the mean position.
• The restoring force shall be proportional to the inertia of body.
• The force and displacement should follow Hooke's law ($F = -kx$), where $k$ is spring constant depends upon the nature of material of spring.
• Acceleration of oscillating object should be proportional to the displacement ($a \propto -x$), the negative sign indicates that acceleration is directed towards mean position.

Interesting Information

lightbulb

It must be noted that not all periodic vibrations are examples of simple harmonic motion since all restoring forces are not proportional to the displacement. Any restoring force can cause oscillatory motion. An electrocardiogram traces the periodic pattern of a beating heart, but the motion of the recorder needle is not a simple harmonic motion. As the restoring force in this case is not always proportional to the displacement from the mean position.