A raindrop with radius \( R = 0.2 \, \text{mm} \) falls from a cloud at a height \( h = 2000 \, \text{m} \) above ground. Assume that the drop is spherical throughout its fall and the force of buoyancy may be neglected, then the terminal speed attained by the raindrop is:
[Density of water \( f_w = 1000 \, \text{kg m}^{-3} \), and Density of air \( f_a = 1.2 \, \text{kg m}^{-3} \), \( g = 10 \, \text{m s}^{-2} \) Coefficient of viscosity of air \( = 1.8 \times 10^{-5} \, \text{N s m}^{-2} \)]
