A raindrop with radius \(\mathrm{R}=0.2\mathrm{mm}\) falls from a cloud at a height \(h=2000 \mathrm{~m}\) above the gro…

A raindrop with radius \(\mathrm{R}=0.2\mathrm{mm}\) falls from a cloud at a height \(h=2000 \mathrm{~m}\) above the ground. Assume that the drop is spherical through its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is :

[Density of water \(f_{\mathrm{w}}=1000 \mathrm{kg m}^{-3}\) and Density of air \(f_{\mathrm{a}}=1.2 \mathrm{~kg}^{-3}, g=10 \mathrm{~m} / \mathrm{s}^{2}\), Coefficient of viscosity of air \(\left.=1.8 \times 10^{-5} \mathrm{Nsm}^{-2}\right]\)