1.State Torricelli's Law for speed of efflux $v = \sqrt{2gh}$ through an orifice at depth $h$ below liquid surface.
2.Calculate work done in blowing a soap bubble of radius $r=5\text{ cm}$ if surface tension $S = 0.03\text{ N/m}$.
3.Eight mercury drops of radius $r=1\text{ mm}$ coalesce to form a single large drop. Find change in surface energy.
