Answer to Question #164333 in Optics for Nidg

Question

          

 

         (a.) A source which is emitting sound waves of frequency fo is travelling at a speed u towards an

         observer who is traveHing with a speed v in the same direction. Derive an expression for the

 frequency f heard by the observer.

Answer 1

$frequency\:of\:source=f_o$

$speed\:of\:source=u$

$frequency\:of\:observer=f$

$speed\:of\:observer=v$

$Speed\:of\:sound\:waves=V$

When observer is moving away from the source: $V-u$

When the source is moving towards the observer: $V-v$

Therefore the overall equation for this case is expressed as:

$f=f_o\left(\frac{V-u}{V-v}\right)$