5. In order to design the geometry of a mold cavity, total solidification time needs to be calculated for the directional solidification. For the design in figure below, the Tst

(riser)=10 min. (9') (1) Select a choice below with suitable TSTfor the sphere and the cube that satisfiesdirectional solidification: (a) Tst (cube) = 5min, Tst (sphere)7min; (b) Tst (cube)5min;= 7min, TST (sphere)= O Based on your selection, if riser is the cylinder with height of 0.1m and diameter of 0.1m, calculate theradius r of the sphere and the side length a of the cube, respectively. (Assume Cm is a constant, n=2)