In the following plane structure shown in Fig 1, rigid blocks are connected by linear spring. Imagine that only horizontal displacements are allowed. For this spring system, write the structure equilibrium equations [K] {D)= {R} in term of spring stiffness K., displacement degree of freedom u, and applied load F. Construct the element matrices and then the global matrix. (10 Marks) Ette 11 (1) 2 F (2) (2) 3 k(3) ww U3 (3) F Fig. 1 F 114 4(5) (5) S 115