A designer wants to know which of the two thin-wall beams can carry greater torsional loading. The two structures have the same wall thickness T. The cross-sectional areas (only the areas of walls) have the same value A. The two beams are made of the same material. (a) Derive equations for their torsional deformations under the same torque Mx (b) Derive equations for their shear stresses under the same torque Mr. (c) If the yield stress is Y, determine maximum torques for the two beams before yield. Hint: you need to use the Tresca's yield condition (d) Compare the determined maximum torques found in (c).