1. Consider the following rotational system that consists of a rotating bar B with moment a f(t) J b f(t) a b J +2 Bj L k Li k J k k L2 Fig.1 of inertia J = 20 Kg m and length Li = 2 m supported by a spring-damper suspension as 1200 N/m and b 50 N sec/m. = = shown in Fig. 1 where k excitation force f(t) = 20 sinut at a distance a = 1.2 m from the rotating point O. Fig. 2 rotating machine results in the a) Compute the transfer function 0(s) G(s) = F(s) where 1(t) is the angular displacement of the bar B. b) Compute the worst-case excitation frequency w" that results in the maximum steady-state angular displacement of the bar B. c) Compute the steady state amplitude of the angular displacement 01 (t) at this excitation frequency w. To eliminate the vibrations of the system at the worst-case excitation frequency w" we include a rotational dynamic vibration absorber B with moment of inertia J and length L = 0.5 m as shown in Fig. 2. d) Compute the transfer function for the coupled system. G(s) = 01(5) F(s) e) Determine the value of the moment of inertia J that will result in the elimination of the vibrations of the bar B at the excitation frequency w.