A police car moving at 22 m/s, chases a motorcylist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observes any beats

Options

A. 33 m/s
B. 22 m/s
C. Zero
D. 11 m/s

Answer

B

Explanation

Frequency of the police car heard by motorcyclist
`f_(1)=((v-v_(m))/(v-v_(S)))f=((330-v_(m))/(330-22))xx176`
Frequency of the siren heard by motorcyclist
`f_(2)=((v+v_(m))/(v))f=((330+v_(m))/(330))xx165`
`f_(1)-f_(2)=0implies((330-v_(m))/(308))xx176=((330+v_(m))/(330))xx165`
`implies v_(m)=22m//s`.