A policeman with a very good ear and a good understanding of the Doppler effect stands on the shoulder of a freeway assisting a crew in a 40-mph work zone. He notices a car approaching that is honking its horn. As the car gets closer, the policeman hears the sound of the horn as a distinct B4 tone (494 Hz). The instant the car passes by, he hears the sound as a distinct A4 tone (440 Hz). He immediately jumps on his motorcycle, stops the car, and gives the motorist a speeding ticket. Explain his reasoning.
The Attempt at a Solution
f0 = f (V(sound) / (V(sound) - V(source)))
since the car is moving toward the policemen it is negative
494Hz = 440Hz * (343 v/s / (343 - V))
and V is 37.166 m/s...
which is obviously not..
i'm not sure where i went wrong probably doppler effect..