$1)$Assemble the system stiffness matrix for the whole skeleton structure;

Figure $1$A skeleton structure is proposed for a sports car, as shown in Figure $1.$ The three members are made from the same material having Young's modulus E of $210000$ MPa and cross section area A of $50m{m}^2$ and are hinged. The length of Member AB is equal to that of Member AC $.$ Assuming the skeleton system is fixed at joint B and simply supported at joint C $,$ and subjected to a downward vertical load $P=10$kNFigure $1$