Two tuning forks with natural freque. ncies 340 Hz each move relative to a stationary observer. One fork moves away from the observer, while the other moves towards him at the same speed. The observer hears beats of frequency 3 Hz. Find the speed of the tuning fork. (Velocity of sound in air = 340 in/s)

Explanation

If speed of tuning for is u,
`Deltaf=f_(A)-f_(R)=f|(2u)/(V)|=3( :.u lt lt V)`
`i.e, u=(V)/(2)[(Deltaf)/(f)]=(340)/(2)[(3)/(340)]=1.5 m//s`