When a drop fall in air the terminal velocity of the drop is \(V _0=\frac{ mg -\frac{4}{3} \pi r ^3 \rho g}{6 \pi \eta r }\) where \(\rho\) is density of air \(\eta\) is the viscosity of air From the above equation \(V _0 \propto \frac{ m }{ r }\)