The alleged answer is that "B" is the only "physical" animation, but I do not see why the block of wood will float higher in this animation as oil is drawn away but before the block of wood breaks the surface of the oil.
By Archimedes Principle and the equilibrium principle, the weight of the block (constant) should equal the weight of the fluids displaced; which would be the sum of the (oil displaced)'s weight and the (water displaced)'s weight. Why would the ratio of these two weights change when the block is less deep under the oil?
If we calculate the buoyancy force based on the difference between the water's pressure pushing up on the bottom surface of the block and the oil's pressure pushing down on the top surface, again I do not see why this "difference" would be different before the oil no longer covers the top surface of the block.
Animation "A" does not seem physical to me because once the block is no longer under the oil, it should sink deeper into the water.
I would appreciate someone else's insight into this.
Thanks,
Stuart Leinoff
Professor of Physics
Science Division Chair
ACC