Doppler Effect (2 moving objects)

[lc99]

Homework Statement

Homework Equations

frequency of observer = frequency of source[(V +- Vo ) / (V-+Vs)]

The Attempt at a Solution

I am not completely understanding this question. I kinda understand that the frequency of the siren does not depend on the distance between the motorcycle and the siren. But, how does it depend on velocity? [/B]

 

[ehild]

Homework Statement

View attachment 221628

Homework Equations

frequency of observer = frequency of source[(V +- Vo ) / (V-+Vs)]

The Attempt at a Solution

I am not completely understanding this question. I kinda understand that the frequency of the siren does not depend on the distance between the motorcycle and the siren. But, how does it depend on velocity? [/B]

The siren is the source, its frequency is given and it does not depend on the velocities. But the frequency of the sound observed by the motorcyclist depends on both the velocity of the source Vs, and the velocity of the observer (Vr).