7 A man standing on a platform observes that the frequency

Last updated: 6/14/2023

7 A man standing on a platform observes that the frequency of the sound of a whistle emitted by a train drops by 140 Hz If the velocity of sound in air is 330 m s and the speed of the train is 70 m s the frequency of the whistle is 1 571 Hz 2 800 Hz 3 400 Hz 4 260 Hz