ω1. The problem statement, all variables and given/known data The following function represents a propagating wave function in a medium f(x,t) = Asin(3π/ λ(x-ct) + a) where A is the amplitude, λ is the wavelength, c is the speed of light in free space, and a is the initial phase. (a) Plot the energy-momentum relation of the wave in the medium (b) Derive an expression for the phase velocity of the wave. 2. Relevant equations 3. The attempt at a solution (a) if I plot energy on one axis and momentum on the other wouldn't graph look like an X= y kind of graph because energy and momentum are proportional? (b) I have the formula vp = ω/k = (dx/dt)φ Where φ is equal to everything after sin. So, do I just take the derivative of (3π/ λ(x-ct) + a)?