(20 points) Determine the nodal displacements, forces in elements 2, and reactions for the three-spring assemblage as shown below. A force of 500 N is applied to the right at node 2. Nodes 1 and 4 are fixed. The spring stiffness's are 15,000 N/m for elements 1 and 3, and 12,000 N/m for element 2.