Question

The sound source of a ship

Answer 1

frequency of sound f=22 KHz

speed of the sound v=1482 m/sec

speed of the source is vs

speed of the observer vo=4.95 m/sec

frequency at observer(whale) n'=n*[(v+vo)/v]    (here source is at rest)

now

here reflector acts as source

frequency at observer(ship) n''=n'*[v/v-vs]   (here observer is at rest)

n''=n'*[v/v-vs]

n''=n*[(v+vo)/v]*[v/v-vs]

=n*[(v+vo)/(v-vs)]

n''=22*10^3*[(1482+4.95)/(1482-4.95)]

=22.147456*10^3 Hz

=22.147456 kHz

now

difference in frequency =n''-n

=(22.147456-22) kHz

=0.147456 kHz

=0.147456*10^3 Hz

=147.456 Hz ......is answer