A motor cycle starts from rest and accelerates along a straight path at `2 m//s^(2)`. At the starting point of the motor cycle there is a stationary electric sire. 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 `= 330 ms^(-1)`)

Options

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

Answer

B

Explanation

For the motor cycle, u = 0 and a = 2 `m//s^(2)`
`therefore n'=n((v-v_(0))/(v+v_(2)))` `rArr(94)/(100)n =n((330-v_(0))/(330))``rArr v_(0)=(99)/(5)m//s` `therefore s= (v^(2)-u^(2))/(2a) = (9 xx 33 xx 33)/(100)= (9 xx 1089)/(100) ~~ 98m `