A raindrop with radius R =0.2 mm falls from a cloud at a height h=2000 m above the ground. Assume that the drop is spherical throughout its fall and…

A raindrop with radius $\displaystyle \mathrm{R}=0.2 \mathrm{~mm}$ falls from a cloud at a height $\displaystyle h=2000 \mathrm{~m}$ above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is : [Density of water $\displaystyle f_{\mathrm{w}}=1000 \mathrm{~kg} \mathrm{~m}^{-3}$ and Density of air $\displaystyle f_{\mathrm{a}}=1.2 \mathrm{~kg} \mathrm{~m}^{-3}$, $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2 $$ Coefficient of viscosity of air $\displaystyle \left.=1.8 \times 10^{-5} \mathrm{Nsm}^{-2}\right]$