Question

A police car's siren has a frequency of 567-Hz while traveling at 24.8-m/s. If the car is coming toward you, and you are stationary, what frequency would you hear?

Answer 1

Fr = ((V+Vr)/V-Vs)) * Fs.
Fr = ((343+0)/(343-24.8)) * 567=611.2Hz.
= Freq. heard by receiver.