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A baseball hits a car, breaking its window and triggering its alarm which sounds at a frequency of 1210 Hz. What frequency (in Hz) is heard by a boy on a bicycle riding away from the car at 8.25 m/s? Take the speed of sound to be 343 m/s.

Respuesta :

Answer:

The frequency of sound heard by the boy is 1181 Hz.

Explanation:

Given that,

Frequency of sound from alarm  [tex]f_{0} = 1210\ Hz[/tex]

Speed = -8.25 m/s

Negative sign show the boy riding away from the car

Speed of sound = 343

We need to calculate the heard frequency

Using formula of frequency

[tex]f = f_{0}(\dfrac{v+v_{0}}{v-v_{s}})[/tex]

Where, [tex]f_{0}[/tex] = frequency of source

[tex]v_{0}[/tex] = speed of observer

[tex]v_{s}[/tex] = speed of source

[tex]v[/tex] = speed of sound

Put the value into the formula

[tex]f=1210\times\dfrac{343+(-8.25)}{343-0}[/tex]

here, source is at rest

[tex]f=1180.8\ Hz[/tex]

[tex]f=1181\ Hz[/tex]

Hence, The frequency of sound heard by the boy is 1181 Hz.

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