A SONAR system fixed in a submarine operates at a frequency 40.0kHz. An enemy submarine moves towards the SONAR with a speed of 360 km`h^(-1)`. What is the frequency of sound reflected by the submarine ? Take the speed of sound in water to be 1450 `ms^(-1)`.

Answer

`45.93 kHz`

Explanation

Frequency received by subnarine
`f_(1)=f_(1) =f_(0)((v)/(v-v_(s)))`
`f_(2)=f_(1)((v+v_(s))/(v))=f_(0)((v+v_(s))/(v-v_(s)))=140((1450+100)/(1450+100))`
`=45.93kHz`