In sоme оf Dоppler's experiments, musiciаns riding on аn open trаin car played notes that were observed by a stationary observer as the train approached and passed by. Calculate the observed frequency as a train approaches an observer given that the frequency the musicians are playing is f= [f] Hz, the velocity of the train is 12.8ms, and the velocity of sound is 341ms. Hint: fobserved=fat the source⋅vwave(vwave)±vtrain.