A stationary observer receives sonic oscillations from two tuning forks one of which approaches and the other recedes with the same velocity. As this takes place, the observer hears the beats of frequency `f = 2.0 H_(Z)`. Find the velocity of each tuning fork if their oscillation frequency is `f_(o) = 680 H_(Z)` and the velocity of sound in air is `upsilon = 340 m//s`.

Explanation

`f_(b) = f_(1) - f_(2) `
`2 = 680 ((340)/(340 - nu_(s))) - 680 ((340)/(340 +nu_(s)))`
`= 680 (1- (nu_(s))/(340))^(-1) - 680 (1+ (nu_(s))/(340))^(-1)`
Using Binomial expansion, we have
`2 = 680 [(2 nu_(s))/(340)] rArr nu_(s) = 0.5 m//s`