Doppler frequency, the other car hear before they pass each other is 668.68 Hz.
What is frequency?
Frequency is the number of occurrences of a repeating event per unit of time.
What is Doppler EFFECT?
The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.
According to the Doppler Effect, the frequency observed is
[tex]fo=fs\frac{v+v_{o} }{v-v_{s} }[/tex]
[tex]f_{o}=595\frac{343+20 }{343-20 }\\f_{o} = 668.68 Hz[/tex]
To know more about Doppler Effect here
https://brainly.com/question/15318474
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