Simple Harmonic Motion
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2. Simple Harmonic Motion

The pressure fluctuations in the air are due to molecules of air vibrating back and forth about their original position but passing on some of their energy of movement. From Eqns. (1) and (2), a particular molecule has a displacement at time t of :

(5)

Then it is moving at a velocity of vibration given by :

(6)

and is being accelerated at a rate :

(7)

Simple harmonic motion is defined as a periodic motion in which :

(i) the acceleration is always directed towards a fixed point in its path, and

(ii) the acceleration is proportional to its distance from the fixed point.