You are standing on a train station platform as a train goes by close to you. As the train approaches, you hear the whistle sound at a frequency of f1 = 94 Hz. As the train recedes, you hear the whistle sound at a frequency of f2 = 72 Hz. Take the speed of sound in air to be v = 340 m/s. Find an equation for the speed of the sound source vs, in this case it is the speed of the train. Find the numeric value, in meters per second, for the speed of the train.
Find an equation for the frequency of the train whistle fs ("s" is for "source") that you would hear if the train were not moving. Express your answer in terms of f1, f2, and v.