A cube of side length 2 m is composed of two materials, separated by a plane slanting down from the top corner to cut the bottom face in a diagonal, as in the figure shown below. The material below the plane has density P gm/m3 and the material above the plane has density Q gm/m3. (a) Find the mass of the portion of the cube below the slanted plane. Your answer will be in terms of P. This is an upper case P.