Suppose you are stopped for a traffic light, and a fast ambulance approaches you from behind with a speed of 34.0 m/s. The siren on the ambulance produces sound with a frequency of 960 Hz. The speed of sound in air is 343 m/s. What is the wavelength of the sound reaching your ears?

Answer 1

f=f₀/{1 – (v/u)}=960/{1- (34/343)} =
=1065 Hz

Answer 2

You forgot to finish the problem.

speed of sound / frequency = wavelength:

343 m/s / 1065Hz = 0.32187 m