Question

Two tuning forks with natural frequencies of `340 Hz` each move relative to a stationary observer. One fork moves away form 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.
A. `1m//s`
B. `1.5 m//s`
C. `340 m//s`
D. `2.5 m//s`

Answer 1

Correct Answer - 2
`f_(1)-f_(2)=3`
`((v)/(v-v_(s)))f-((v)/(v+v_(s)))f=3`
so `v_(s) =(3V)/(2f)=(3)/(2)xx(340)/(340)`
`v_(s)=(3)/(2)=1.5 m//s`