A solid homogeneous block is completely immersed in a liquid and held stationary by a string attached to the bottom of the container.
(i) Define buoyant force.
(ii) Explain, on the basis of variation of pressure with depth, why the block experiences an upward force rather than a downward force.
(iii) Give two reasons to justify that, for a body fully submerged at any depth, the magnitude of this upward force depends only on the volume of the body and not on the depth of immersion.