A motor cycle starts from rest and accelerates along a straight path at `2m//s^(2)`. At the starting point of the motor cycle there is a stationary electric siren. How far has the motor cycle gone when the driver hears the frequency of the siren at `94%` of its value when the motor cycle was at rest ? (Speed of sound = `330ms^(-2))`

Options

A. `49 m`
B. `98 m`
C. `147 m`
D. `196 m`

Answer

B

Explanation

`{:(rarr v_(s) = 0,, larr v_(o)),(overset(*)(S),overset(v)rarr,overset(*)(O)^(f')):}`
`f' = f((v-v_(0))/(v))`
`0.94f = f((330-v_(0))/(330))`
`v_(0) =19.8 m//s`
`v_(0)^(2) = u^(2) + 2as`
`(19.8)^(2) = 0+2 xx 2 xx s`
`s = 98 m`