1. The problem statement, all variables and given/known data An observer is in rest.A source of sound is in rest.A wind blows along the line joining the observer and the source.What all remain same in these: a.frequency b.velocity of sound c.wavelength 2. Relevant equations f prime=f(v+w-vo)/(v+w-vs) Doppler effect 3. The attempt at a solution frequency has to remain same since there is no relative motion. v should remain same because wind cannot influence speed of sound. wavelength has to obviously remain the same (from the above). But my book says only frequency remains same. Please explain.