Answer:
The apparent frquency would be
f' = 493.26 Hz
Step-by-step explanation:
This a Doppler's effect problem. This effects produces a slight change in the frequency of a traveling wave, due to the effect of the velocity of the receiver (observer).
The formula used to describe the change, as both vehicles are moving away of each other:
f' = [ (Vwave + Vobserver) / (Vwave + Vsource ) ]*f
Where
Vwave = 340 m/s ( speed of sound)
Vobserver = 18.6 m/s (observer = car)
Vsource = 23.5 m/s (speed of the ambulance = source)
f = 500 Hz (frequency of the sound)
We just need to substitute in the equation
f' = [(340+ 18.6) / (340+ 23.5)] * 500 Hz
f' = [0.9865] * 500 Hz = 493.26 Hz
f' = 493.26 Hz
