A railroad train is travelling at `30 m//s` in still air. The frequency of the note emitted by the node emitted by the locomotive whistle is `500 H_(Z)`. What is the wavelength of the sound waves : (a) in front of the locomotive?
What is the frequency of the sound heard by a stationary listener (b) behind the locomotive? (c) in front of the locomotive ?
Speed of sound in air `344 m//s`. (d) behind the locomotive ?

Explanation

In front of locomotive, `f' f ((nu)/(nu - nu_(s)))`
`= 500 ((344)/(344 - 30)) = 548 H_(Z)`
`:. lambda' = (nu)/(f') = (344)/(548) = 0.628 m`
Behind the locomotive,
`f' f ((nu)/(nu + nu_(s)))`
`= 500 ((344)/(344 + 30)) = 460 H_(Z)`
`:. lambda' = (nu)/(f') = (344)/(460) = 0.748cm`