A square steel tube of length L = 20 ft and width b2 = 10.0 in. is hoisted by a crane (see figure on the next page). The tube hangs from a pin of diameter d that is held by the cables at points A and B. The cross section is a hollow square with inner dimension b₁ = 8.5 in. and outer dimension b2 = 10.0 in. The allowable shear stress in the pin is 8,700 psi, and the allowable bearing stress between the pin and the tube is 13,000 psi Determine the minimum diameter of the pin in order to support the weight of the tube. (Note: Disregard the rounded corners of the tube when calculating its weight.)
