A policeman on duty detects a drop of 10% in the potch of the horn of motion of car as ot crosses him. If the velocity of sound is 330m/s. Calculate speed of the car. AnAns is 17.4 m/s

Dear Student,

Please find below the solution to the asked query:

Given that the police man detects 10% drop in the pitch when the car crosses him. So, the apparent frequency when the car moves away from him is 90% of the apparent frequency when the car approaches him. Therefore,

When car approaches him,

ν1=νVV-Vs
The apparent frequency, when the car moves away,

ν2=νVV+Vs
Therefore, from the given information,

ν2=0.9ν1  0.9 νVV-Vs=νVV+Vs  9V+Vs=10V-Vs 19Vs=V Vs=33019Vs=17.4 ms

 

 

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