The axially loaded bar 1–4 of constant axial rigidity AE is held between two rigid suppo...

The axially loaded bar 1–4 of constant axial rigidity AE is held between two rigid supports and under a concentrated load P at node 3, as illustrated in Fig. P7.18. Find (a) the system stiffness matrix; (b) the displacements at nodes 2 and 3; (c) the nodal forces and reactions at the supports.