1. (20%) A rigid body system shown in Figure 1. Use u(t) as the degree of freedom (DOF) of the system. The total mass of the rigid disk is m m and the rigid bar AB m2 1.5m. The radius of the disk is L. The rigid bar and the disk are connected by an inextensible cable. Derive the dynamic governing equation of motion by using Lagrange's Equation of Motion. A p(t) 2L m2 C L - B mi u(t) 2L Figure 1: A rigid body system k