(a) Name the forces acting on a body, when it is fully or partially immersed in a liquid. (b) Briefly explain, why some objects float and some sink

(a) The forces acting on a body are :
(i) Buoyant force acting in upward direction, and
(ii) Weight of the object in the downward direction.
(b) An object sinks if W > U and an object floats when W < U, where W is the weight of the body and U is the buoyant force.