a solid cylinder of 50 mm diameter and 900 mm length is subjected to a tensile force of 120kN. One part f the cylinder L1 long is of steel, the other part, fastened to steel, is aluminum and is L2 long. Determine lengths L1 and L2 so the two materials elongate an equal amount. What is the total elongation of the cylinder? Est=200GPa; EAl=70GPa