The free response of a 2DoF mass-spring system is given below: x(t) = cos2t+cos3t and x2(t) = 6cos2t-4cos3t The mass associated with 2 (t) is m = 1 kg. Answer the following questions: (A) [6/40] What are the natural frequencies of the system? (B) [3/40] What is the characteristic equation of the system? (C) [15/40] Compute the first and second mode shape of the system, u and ? (D) [16/40] Determine the rest of the system parameters, i.e. spring constants k and k2 and the mass associated with x (t), m. m1 x1 m2 k x2