I NEED HELP PLEASE! :) A train is moving at 23 m/s due east when it sounds a blast on its horn, frequency = 164 Hz. What frequency is

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I NEED HELP PLEASE! 🙂
A train is moving at 23 m/s due east when it sounds a blast on its horn, frequency = 164 Hz. What frequency is heard by the driver of a car moving due east at 15 m/s along a road parallel to the tracks? Use 343 m/s for the speed of sound. Please show all work.

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Thu Hương 5 years 2021-08-23T00:17:18+00:00 1 Answers 8 views 0

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  1. taiduc
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    2021-08-23T00:19:08+00:00
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    Answer:

    168 Hz

    Explanation:

    The Doppler equation describes how sound frequency depends on relative velocities:

    fr = fs (c + vr) / (c + vs),

    where fr is the frequency heard by the receiver,

    fs is the frequency emitted at the source,

    c is the speed of sound,

    vr is the velocity of the receiver,

    and vs is the velocity of the source.

    Note: vr is positive if the receiver is moving towards the source, negative if away.

    Conversely, vs is positive if the receiver is moving away from the source, and negative if towards.

    Given:

    fs = 164 Hz

    c = 343 m/s

    vr = -15 m/s

    vs = -23 m/s

    fr = fs (c + vr) / (c + vs)

    fr = 164 Hz (343 m/s − 15 m/s) / (343 m/s − 23 m/s)

    fr = 168 Hz

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