10.4 (si units) a disk with diameter = 40 cm and thickness = 5 cm is cast of pure aluminum in an open mold casting operation. aluminum melts at 660°c, but the pouring temperature will be 800°c. the heat of fusion of aluminum = 398 j/g. other properties can be found in tables 4.1 and 4.2. assume that the specific heat has the same value for solid and molten aluminum. compute (a) the unit energy for melting and pouring and (b) the total energy to heat the metal to the pouring temperature starting from a room temperature of 25°c.