A sound source, fixed at the origin, is continuously emitting sound at a frequency of 660 Hz. The sound travels in air at a speed of 330 m s -1 . A listener is moving along the line x=336 m at a constant speed of 26 m s -1 . Find the frequency of the sound as observed by the listener when he is (a) at y = — 140 m, (b) at y = 0 and (c) at y = 140 m.

A sound source, fixed at the origin, is continuously emitting sound at a frequency of 660 Hz. The sound travels in air at a speed of 330 m s^-1. A listener is moving along the line x=336 m at a constant speed of 26 m s^-1. Find the frequency of the sound as observed by the listener when he is (a) at y = — 140 m, (b) at y = 0 and (c) at y = 140 m.

(a) When the observer is moving in –y direction, the apparent frequency will be,

(b)

At y=0 the observer is at x = 360m.

So,

(c)

When the observer is moving in y direction, the apparent frequency will be,

1