A railroad boxcar of mass 18000 kg and traveling at a velocity of v1.3 m/s is stopped at the end of the tracks by a spring damper system, as shown in Fig. 4(b). The stiffness of the spring is k 73000 N/m and the damping constant is c = 88000 N.s/m. Answer each of the following: (i) Calculate the damping ratio. (ii) Calculate the natural frequency of the system. (iii) Develop an expression describing the velocity with respect to time. (iii) Determine the maximum displacement of the barrier. m Fig. 4(b) www