5.65 Determine the equations of motion and the natural frequencies of the system shown in Fig. 5.56. k m1 00000 m2, Jo FIGURE 5.56 Two masses connected by a spring. 5.65 for the disk, take the sum of the moments about the contact point on the ground and include the ma and Jw terms rather than using the equivalent mass. You could also use equivalent KE to derive the equivalent mass equation but you cannot just write that equation down.