Physics - Fluid Question with Solution | TestHub

Radius of drop, $\mathrm{r}=0.3\mathrm{mm}=0.03\mathrm{cm}$ Terminal velocity, $\mathrm{v}=1\mathrm{m}/\mathrm{s}=100\mathrm{cm}/\sec$ Viscosity of air, $\eta =8\times 10^{-5}$ poise Viscous force, $\mathrm{f}=6\pi \eta \mathrm{rv}$ $$\begin{array}{l}\mathrm{F}=6\times 3.14\times \left(8\times 10^{-5}\right)\times 0.03\times 100=4.52\\ \times 10^{-3}\text{ dyne }\end{array}$$