A policeman on duty detect a drop of 10% in the pitch of the horn of motion of car as it crosses him . IF the velocity of sound is 330 m/s . Calculate the speed of the car .

Options

A. `20 m//sec`
B. `17.3 m//sec`
C. `25 m//sec`
D. `27 m//sec`

Explanation

`f_(1)//f_(2)=[(c )/(c-v)//(c )/(c+v)]`
`rArr (f_(1))/(f_(2))=(c+v)/(c-v)rArr (100)/(90)=(c+v)/(c-v)`
`rArr 100c-100v=90C+90v`
`rArr 10c=190v`
`rArr 1//19xx330=17.3m//s`