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A stationary horn emits a sound with a frequency of 228 Hz. A car is moving toward the horn on a straight road with constant speed. If the driver of the car hears the horn at a frequency of 246 Hz, then what is the speed of the car? Use 340 m/s for the speed of the sound

User Jmlevick
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1 Answer

2 votes

Answer: 26.84 m/s

Step-by-step explanation:

Given

Original frequency of the horn
f_o=228\ Hz

Apparent frequency
f'=246\ Hz

Speed of sound is
V=340\ m/s

Doppler frequency is


\Rightarrow f'=f_o\left((v+v_o)/(v-v_s)\right)

Where,


v_o=\text{Velocity of the observer}\\v_s=\text{Velocity of the source}

Insert values


\Rightarrow 246=228\left[(340+v_o)/(340-0)\right]\\\\\Rightarrow 366.84=340+v_o\\\Rightarrow v_o=26.8\ m/s

Thus, the speed of the car is
26.84\ m/s

User Justin Swartsel
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