A block floating on water contained in a vessel is pushed inside until it touches the bottom of the vessel and then released. Will the block come back?
Bouyant force acts because the pressure on the bottom of the block is more than that at the top.
If the block was cubical and its top surface is at a distance $h$ from the surface of water, and had a side length $a$, then the pressure on top will be $P_0+\rho gh$
Pressure on bottom surface will be $P_0+\rho g(h+a)$
Pressure difference = $\rho g a$.
Force acting is = $\rho g a\cdot a^2=a^3\rho g$
If the bottom surface of the cube were to touch the bottom of vessel, then there is no water beneth it to exert pressure upwards. So won't the block remain in the bottom even if its density is less than that of the liquid?
