Question

a policeman blows a whistle of frequency 300 Hertz as a car speed post him with a velocity of 18 km/h. find the change in frequency as head by the driver of car just as passes the policeman velocity of sound =340 m/s​

Answer 1

Answer:

If the car approaches the policeman

υ

′

=

ν−ν

s

ν−ν

0

×υ=

300−0

300−(15)

×500⟹υ

′

=525Hz

If the car moves away from the policeman

υ

′′

=

ν−ν

S

ν−ν

0

×υ=

300−0

300−15

×500Hz

υ

′′

=475Hz

Change in frequency =υ

′

−υ

′′

=525−475=50Hz