A flat bar of width b = 60 mm and thickness t 10 mm is loaded in tension by a force P (see figure). The bar is attached to a support by a pin of diameter d that passes through a hole of the same size in the bar. The allowable tensile stress on the net cross section of the bar is σ_T= 140 MPa, the allowable shear stress in the pin is t_S = 80 MPa, and the allowable bearing stress between the pin and the bar is σ_B = 200 MPa.

(a) Determine the pin diameter d_m for which the load P will be a maximum.

(b) Determine the corresponding value P_max of the load.