1. The problem statement, all variables and given/known data A car honks a 2kHz tone and is 40m from a long high wall. A man is running parallel to the wall, 10m away from it, at 5 m/s, and is presently 30m away from where the whistle is closest to the wall. How many beats/second will be heard by the runner as he will hear the direct whistle signal and the one reflected from the wall. 2. Relevant equations 3. The attempt at a solution I have drawn a diagram and also knw that this problem has to do with the Doppler effect. But i am not sure where to start.