Apolice car has an 800-hz siren. it is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s. the car approaches and passes an observer who is standing along the roadside. what change of frequency does the observer hear?

The change of frequency does the observer hear due to police car siren is 6971.42 Hz.

Frequency of wave is the number of waves, which is passed thorough a particular point at a unit time.

For the cars approaching to the observer, the Doppler formula can be given as

Here, is the speed of the sound.

A police car has an 800-Hz siren. It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s.

As, the car approaches and passes an observer. Thus by the above formula,

As the frequency of police car siren is 800-Hz. Thus, the change of the frequency observed by the observer is,

Thus, change of frequency does the observer hear due to police car siren is 6971.42 Hz.

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The observer experienced a change I'm frequency of 6971.42Hertz

Explanation:

In waves, the frequency of a wave is directly proportional to its velocity i.e F ∝ V

F = kV

k = F/V

F1/V1 = F2/V2 = k... 1

Given F1 = 800Hz at V1 = 35m/s

F2 = ? when V2 = 340m/s

Substituting this given datas into equation 1 to get the new frequency F2:

800/35 = F2/340

35F2 = 800×340

F2 = 800×340/35

F2 = 7771.42Hertz

Change of frequency = F2-F1

Change of frequency = 7771.42-800

Change of frequency = 6971.42Hertzz

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