3) (40 points) Two metal sheets, as shown below, are bolted together in compression using four #5-44 UNF 1/2-in SAE grade 4 bolts. The bolt stiffness is 150 kips/in and the effective stiffness of the two metal sheets is 750 kips/in. If a total force of 93.75 lb is applied to the two metal sheets as shown, determine: a) The minimum required pretension on one single bolt, assuming the force is equally distributed over all 4 bolts, to prevent the joint from separating. b) The torque required to tighten the one single bolt to the pre-tension determined in part a) if the bolt is cadmium-plated (Hint: Find the torque factor K from Table 8-15). c) The proof stress factor of safety for one single bolt when the force is applied, assuming the load on the motor plate is equally distributed over all 4 bolts, if the installed pre-tension is 75% of the bolt's rated proof strength. 3 Metal Sheet A 93.75 lbf I Metal Sheet B Bolts (4 bolts threaded through Metal Sheet A and Metal Sheet B; 2 bolts visible here)