An aluminium strut 6 ft long has a rectangular section 0.75 inch by 2 inch. A bolt through each end secures the strut so that it acts as hinged column about an axis perpendicular to the 0.75-inch dimension, and as fixed ended column about an axis perpendicular to the 2.0 in dimension. Determine the safe central load, using a factor of safety 0f 1.75 and E = 10 ×106 psi.