1. The problem statement, all variables and given/known data If you take snapshots of a standing wave on a string, there are certain instants when the string is totally flat. What has happened to the energy of the wave at those instants? 3. The attempt at a solution I'm assuming that nothing has happened to the energy. At that instant in time, even if the displacement of the wave is zero, it does not imply that the wave is stationary, therefore, it still has a velocity. Thus, there remains kinetic energy in the wave. Am I on the right track?