4. Consider the system shown below. It is excited by harmonic base motion y(t) = 0.02 sin(wt) [m] where wo is the excitation frequency. www k HG Ha x(1) y(t) m C m = 3 kg k= 2000 N/m k = 5000 N/m C = 40 Ns/m C = 30 Ns/m (a) Determine the equation of motion of the system. (b) Calculate the maximum displacement amplitude and the corresponding phase angle of the mass m. (c) Plot the transmissibility of displacement from the base to the mass with respect to the frequency ratio co/on and indicate the region where transmissibility is greater than unity.