A cube of oak wood with very smooth faces normally floats in water. Suppose you submerge it completely and press one face flat against the bottom of a tank so that no water is under that face. Will the block float to the surface? Is there a buoyant force on it? Explain.
Buoyant force is a well known consequence of pressure difference across fluids, and if there's no fluid under the object then there should be no buoyant force?
Practically speaking, the block should rise to the surface again.(I tried it) However, according to my understanding of fluid mechanics, as long as there is no net upward force on the block, it can't start moving upwards
Could someone please explain this, and also tell whether buoyant force really does vanish if the block is pushed to the bottom of the vessel?