Answer:
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
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
[tex]\dfrac{f_1}{v_1}=\dfrac{f_2}{v_s}[/tex]
Here, [tex](v_s)[/tex] 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,
[tex]\dfrac{800}{35}=\dfrac{f_2}{340}\\f_2=7771.41\rm Hz[/tex]
As the frequency of police car siren is 800-Hz. Thus, the change of the frequency observed by the observer is,
[tex]\Delta f=7771.42-8000\\\Delta f=6971.42\rm Hz[/tex]
Thus, change of frequency does the observer hear due to police car siren is 6971.42 Hz.
Learn more about the frequency here;
https://brainly.com/question/1436295
