Answer:
Yes they hear different frequencies when they are moving as compared to when they are at rest.
Explanation:
The difference in the frequencies of sound that we hear when an object moves and when it is at rest is a phenomenon known as Doppler's effect of sound and the difference in the heard frequencies is known as Doppler shift.
The frequency that we perceive if the source is moving is given by
[tex]f_{perceived}=(\frac{c\pm v_{r}}{c\pm v_{s}})f_{o}[/tex]
where
'f' is the perceived frequency
[tex]f_{o}[/tex] is the original frequency
c is velocity of sound
[tex]v_{s},v_{r}[/tex] are the velocity of source and velocity of receiver respectively
