1. The problem statement, all variables and given/known data Suppose a person is fishing and is bobbing the fishing pole in constant intervals, there are 2 fish in the water located in the same distance L from the fishing pole (the source of the wave). Suppose also the water is moving from A to B. Which fish will feel the wave first? 2. Relevant equations & The attempt at a solution Firstly I hope the problem statement is clear as it was translated. Do you believe the answer is uniquely determined? To me it seems to depend on the velocity of the water and the the period Of the wave. If only one wave was created and the water was moving with the fish with it, both fish would feel the wave in the same time. But if the water was moving fast, with the appropriate period of the wave, you might create a situation where fish A would get hit by the second wave before the first wave. (Perhaps by hitting the fish with the hook of the fishing pole) The answer given is both fish would feel the wave in the same time by considering the reference frame of the water. But does this answer really considers the case I gave?