3. A 10-ft hollow steel shaft with a circular cross section shown below is used in a power generation/transmission system. The shaft has inner and outer diameters of 3 and 5 inches, respectively. The steel has an allowable shear stress 10 ksi. Please determine the maximum torque that can be transmitted by, and the associated angle of twist for, (a) the shaft with the above given geometry and dimensions, and (b) a solid shaft made of the same material with the same weight. (The density of the steel is 0.29 lb/in³.) T B A