1. The problem statement, all variables and given/known data If y(x, t) = (6.7 mm) sin(kx + (705 rad/s)t + ϕ) describes a wave traveling along a string, how much time does any given point on the string take to move between displacements y = -2.0 mm and y = +2.0 mm? 2. Relevant equations I'm not sure where to start. 3. The attempt at a solution That's the problem.