Learning Goal:

To understand the terms in the Doppler shift formula.

The Doppler shift formula gives the frequency $f_L$ at which a listener $L$ hears the sound emitted by a source $S$ at frequency $f_S$ :

$f_L=f_S\frac{v+v_L}{v+v_S}$

where $v$ is the speed of sound in the medium, $v_L$ is the velocity of the listener, and $v_S$ is the velocity of source.

The velocity of the source is positive if the source is $q,$ Note that this equation may not use the sign convention you are accustomed to$.$ Think about the physical situation before answering.

View Available Hint$($s$)$

traveling in the $+x$ direction

traveling toward the listener

traveling away from the listener