Answer
(a) Both cubes displace the same amount of water, so by Archimedes' Principle, both cubes experience the same buoyant force.
(b) The tension in the wire holding the lead cube is greater because the lead cube is heavier than the aluminum cube.
(c) The lead cube is lower in the water so it experiences a greater upward force on its lower face.
(d) The difference in pressure between the upper and lower faces is equal for both cubes.
Work Step by Step
(a) Both cubes displace the same amount of water, so by Archimedes' Principle, both cubes experience the same buoyant force.
(b) The tension in the wire holding the lead cube is greater because the lead cube is heavier than the aluminum cube. Note that the density of lead is greater than the density of aluminum.
(c) The lead cube is lower in the water so it experiences a greater upward force on its lower face.
(d) The difference in pressure between the upper and lower faces is equal for both cubes. The pressure difference is equal to $\rho_{water}~g~(\Delta h)$. Since $\Delta h$ is the same for both cubes, the pressure difference is the same for both cubes.
