Two sources of sound `S_(1)` and `S_(2)` produce sound waves of same frequency `660 Hz`. A listener is moving from source `S_(1)` towards `S_(2)` with a constant speed `u m//s` and he hears `10` beats/s. The velocity of sound is `330 m//s`. Then, `u` equals :

Answer

2.5

Explanation

`f_(1)=f_(0)((v-u)/v)` and `f_(2)=f_(0)((v+u)/v)`
`f_(2)-f_(1)=(f_(0))/v2uimpliesu=(v(f_(2)-f_(1)))/(2f_(0))=(330xx10)/(2xx660)=2.5m//s`