13.(SI units) Total solidification times of three casting geometries are to be compared: (1) a sphere with diameter = 10 cm, (2) a cylinder with diameter and length both casting

alloy is used in all three cases. (a) Determine the relative solidification times for each geometry. (b) Based on the results of part (a), which geometric element would make the best riser? (c) If the mold constant = 3.5 min/cm? in Chvorinov's rule, compute the total solidification time for each casting. (6')= 10 cm, and (3) a cube with each side = 10 cm. The same