Answer to Question #330732 in Electrical Engineering for Gintoki

Question

Determine the frequency of sound heard by a stationary listener when a moving siren emits 550Hz and travels away at 50m/s from the listener assuming the air temperature is 20 degree Celsius.

Answer 1

$$f=f_0\frac{c}{c+v}$$

$$f=550*\frac{343}{343+50}=480\;\rm Hz$$