1. The problem statement, all variables and given/known data A train passes a person at a constant speed of 40.0m/s. The train horn is sounded at its characteristic frequency of 320 Hz. 2. Relevant equations a) What overall change in frequency is detected by the person as the train moves from approaching to receding? b) What wavelength is detected by the person as the train approaches? 3. The attempt at a solution I already solved A. I got a change of -74.2 Hz. 282Hz for approaching and 357.1Hz for receding. I have absolutely no idea how to do part B. I tried using V = "lambda"f (a.k.a. velocity = wavelength * frequency) but it didn't work.