"An ambulance is traveling north at 45.3 m/s, approaching a car that is also traveling north at 33.9 m/s. The ambulance driver hears his siren at a frequency of 656 Hz. Ambulance 45.3 m/s 33.9 m/s Car At what frequency does the driver of the car hear the ambulance’s siren? The velocity of sound in air is 343 m/s. Answer in units of Hz."