A spherical raindrop $2\mathrm{.}1$ mm in diameter falls through a vertical distance of $4450$ m$.$ Take the cross$-$sectional area of a raindrop $=$r$2,$ drag coefficient $=0\mathrm{.}45,$ density of water to be $1000$ kg$/$m$3,$ and density of air to be $1\mathrm{.}2$ kg$/$m$3.$

$($a$)$

Calculate the speed $($in m$/$s$)$ a spherical raindrop would achieve falling from $4450$ m in the absence of air drag.

m$/$s

$($b$)$

What would its speed $($in m$/$s$)$ be at the end of $4450$ m when there is air drag?

m$/$s