a uniform block of granite in the shape of a book has face dimensions of 18 cm and 13 cm and a thickness of 1.2 cm. the density (mass per unit volume) of granite is 2.64 g/cm3. the block rotates around an axis that is perpendicular to its face and half way between its center and a corner. its angular momentum about that axis is 0.104 kg · m2/s. what is its rotational kinetic energy about that axis?