A train at rest emits a sound at a frequency of 1057 Hz. An observer in a car travels away from the sound source at a speed of 20.6 m/s. Wha

Question

A train at rest emits a sound at a frequency of 1057 Hz. An observer in a car travels away from the sound source at a speed of 20.6 m/s. What is the frequency heard by the observer

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Ladonna 5 years 2021-08-19T18:15:29+00:00 1 Answers 38 views 0

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  1. Delwyn
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    2021-08-19T18:17:01+00:00
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    Answer:

    993.52 Hz

    Explanation:

    The frequency of sound emitted by the stationery train is 1057 Hz.

    The car travels away from the train at 20.6 m/s.

    The frequency the observer hears is given by the formula:

    f_o = \frac{v - v_o}{v}f

    where v = velocity of sound = 343 m/s

    vo = velocity of observer

    f = frequency from source

    This phenomenon is known as Doppler’s effect.

    Therefore:

    f_o = \frac{343 - 20.6}{343} * 1057\\ \\f_o = 322.4 / 343 * 1057\\\\f_o = 993.52 Hz

    The frequency heard by the observer is 993.52 Hz.

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