The classic example of the Doppler effect is the change in pitch of a locomotive's whistle as it passes by.If the speed of sound is 330 m/s, the speed of the train(Vtr) is 80 km/h, the frequency of the sound, which the steam whistle yield (fs) is 800 Hz, the man is static. When the train moves towards to the man, what is the frequency of the sound produced by the whistle which the man hear? When the train moves away from the man, what is the frequency of the whistle sound which the man hears?