4.10 The SDOF system in Fig. P4.10 is subjected to harmonic excitation z(t) = Z cos omega(t) applied at point P. Express your answers to the following in terms of the givens: m, c, k, Z, and Omega (a) Derive the equation of motion of the system with the absolute displacement u(t) as the unknown, (b) Derive the equation of motion of the system with the relative displacement w(t) = z- u as the unknown, (c) Determine expressions for Wn and Zeta(damping ratio) for this system, (d) Determine expressions for the following complex-frequency-response functions: U/Z and W/Z. k/2 M-m Q2t WWW k/2 Figure P4.9 u