What is the observed frequency of a siren with a frequency of 440 Hz moving away from you at 25 m/s? The speed of sound is 330 m/s.

We use the equation f_{f}
= f_{0} (v/ (v + v_{0})) , and we plug in our given values to
get

f_{f} = 440 (330/ (330 +
25) = 410 Hz