A2640-hz sound source is moving at 15.0m/s toward a stationary observer. what is the frequency heard by the observer if the speed of sound is 343 m/s?

The frequency heard by the observer is 2760.73 hertz.                 Explanation:

Frequency of source, f = 2640 Hz

Velocity of source,

The speed of sound, v = 343 m/s

Let f' is the frequency heard by the observer. According to Doppler's effect, the frequency of the observer is given by :

(as the source is moving towards observer)

f' = 2760.73 Hz

So, the frequency heard by the observer is 2760.73 hertz. Hence, this is the required solution.                              

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