Let x represent the motion of the block shown below where all seven springs are unstretched when x = 0. (a) Determine the equivalent stiffness of the system. Show all of your calculations. (b) Derive the differential equation of motion for the system shown below in terms of the coordinate x. You need to include appropriate free body diagrams in your work. 3k I F m 3c 2c lc k 2k Figure 2: Translational mechanical system with elements in series and parallel.