Question
A policeman on duty detects a decrease of 12% in the pitch of horn from a car crossing him. Find the velocity of car. The velocity of sound in air is 340m/s.
Solution
The apparent pitch of horn while car is approaching before crossing is,
The apparent pitch of horn after crossing is,
The percentage drop in pitch is given by,
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We have, the percentage drop in pitch is 12%.
So,
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, is the velocity of the car.
The apparent pitch of horn after crossing is,
The percentage drop in pitch is given by,
We have, the percentage drop in pitch is 12%.
So,
, is the velocity of the car.
