I have been working on this problem for over a half hour. I'm not sure where I'm going wrong with it. If anyone could help me out I would really appreciate it. You stand by the railroad tracks as a train passes by. You hear a 1000 Hz frequency when the train approaches, which changes to 800 HZ as it goes away. How fast is the train moving? The speed of sound in air is 340 m/s. I have been trying fo = f*Vsound/Vsound +- Vs and then trying to set them equal, but it isn't working for some reason Any ideas? Thanks a lot!