A cube of side 100 mm is placed at the bottom of an empty container on one of its faces. The density of the material of the cube is 800 kg/m3.

Q. A cube of side 100 mm is placed at the bottom of an empty container on one of its faces. The density of the material of the cube is 800 kg/m³. Liquid of density 1000 kg/m³ is now poured into the container. The minimum height to which the liquid needs to be poured into the container for the cube to just lift up is_____mm.

Sol:

To just lift the block from the bottom,
Weight of cube = FB
⇒ρg×V=ρig×∀
⇒800×a3=1000×a2×h
⇒h=0.8×a
=0.8×100=80mm