21. Mercury 3 g is placed between two parallel glass plates. Determine the force that must be applied to flatten to a thickness of drop d = 0,1 mm. Mercury does not wet glass. Mercury density ρ = 13,6 g / cm3, and its surface tension σ = 0,5 N / m.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)