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

Options

A. `33m//s`
B. `22m//s`
C. `zero`
D. `11m//s`

Answer

B

Explanation

(b) `f_(1) = frequency of the police car heard by motorcyclist`,
`f_(2) = frequency of the siren heard by motorcyclist`.
`f_(1) = (330-v)/(330 - 22) xx 176` , `f_(2) = (330 + v)/(330) xx 165` ,
`because` `f_(1) - f_(2) = 0 rArr v = 22 m//s`