(20 points) Prismatic bars of various thin-walled cross-sections of uniform thickness t (shown below) are to be loaded in torsion. Calculate the torsion constant for each shape below, Ji (i = 0, 1, ..., 4). R C (0) (1) circular arc (4) h a 10 h. /10 1 (2) (20 points) For the previous problem, assume they are made of the same material and are sized to have the same weight. Calculate the ratios Jo/Ji, where Jo is the torsion constant of the circular shape and Ji (i = 1, ..., 4) are those of the non-circular shapes.