An empty cylinder glass ABCD with mass m, height H with inferior base s and exterior base S. We fill completely the glass with water then we close the surface AD with our hand so that we could put the glass upside down on a tank of water. The glass float with height h submerged in the water. Find the force applied by the operator on the glass to maintain the equilibrium: a. By the balance of pressing force
b. By the theorem of Achimades​