I am trying to plot a phase angle vs. frequency curve numerically for steady state condition of the following equation

x''[t] + 2*\[Zeta]* x'[t] + x[t] == Cos[w*t]

where w is the forcing frequency, and the initial conditions are x[0] == 0, x'[0] == 0. A similar plot is shown here.

Any help would be highly appreciated. Thanks