A siren mounted on the roof of a firehouse emits sound at a frequency of 900 Hz. A steady wind is blowing with a speed of 15.0 m/s. Taking the speed of sound in calm air to be 343 m/s, find the wavelength of the sound (a) upwind of thesiren and (b) downwind of the siren.

Question

Physics

Ricky Bradford

14 October, 01:34

A siren mounted on the roof of a firehouse emits sound at a frequency of 900 Hz. A steady wind is blowing with a speed of 15.0 m/s. Taking the speed of sound in calm air to be 343 m/s, find the wavelength of the sound (a) upwind of thesiren and (b) downwind of the siren.

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Answers (1)

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Elijah Flynn · Answer 1

upwind wavelength = 0.3644 m

downwind wavelength = 0.3977 m

Explanation:

given data

frequency f = 900 Hz

speed v = 15.0 m/s

speed of sound s = 343 m/s

to find out

wavelength of the sound upwind and downwind

solution

we will apply here formula for upwind wavelength that is

upwind wavelength = (s - v) / f

put here all these value

upwind wavelength = s - v / f

upwind wavelength = (343 - 15) / 900

upwind wavelength = 0.3644 m

and

downwind wavelength = (s + v) / f

put here all these value

downwind wavelength = (343 + 15) / 900

downwind wavelength = 0.3977 m