1. [20 pt.] Four gears are attached to a circular shaft and transmit the torques shown in the figure. The allowable shear stress in the shaft is 10,000 psi. a. What is the required diameter d of the shaft if it has a solid cross section? b. What is the required outside diameter d if the shaft is hollow with an inside diameter of 1.0 in.? 8,000 lb-in. 19,000 lb-in. A B 4,000 lb-in. 7,000 lb-in. C D