The pin-ended members AB and BC as shown in Figure P4 consist of sections of aluminum pipe of 120 mm outer diameter and 10 mm wall thickness. Knowing that a factor of safety of 3.5 is required, determine the mass m of the largest block that can be supported by the cable arrangement shown for values of h from 4 m to 8 m, using 0.25-m increments. Use E = 70 GPa and consider only buckling in the plane of the structure. 4 m 3m D M Figure P4 3m d