The terminal velocity of a liquid drop of radius $r$ falling through air is $v$. If two such drops are combined to form a bigger drop,the terminal velocity with which the bigger drop falls through air is (ignore any buoyant force due to air).

The unit of the coefficient of viscosity in the $S.I.$ system is

$A$ ball is thrown downward with some initial velocity into a viscous liquid. Which of the following curves represents the correct variation of velocity versus time?

Eight equal drops of water are falling through air with a steady velocity of $10 \,cm \,s^{-1}$. If the drops combine to form a single drop, then the terminal velocity of this big drop is:

$A$ spherical solid ball of volume $V$ is made up of a material of density $\rho$. It is falling through a liquid of density $\sigma$ $(\sigma < \rho)$. Assume that the liquid applies a viscous force on the ball that is proportional to the square of the terminal speed $v_{T}$,$F = -K v_{T}^2$ $(K > 0)$. Then,the terminal speed of the ball is ($g =$ acceleration due to gravity).

$A$ lead sphere of mass $m$ falls in a viscous liquid with terminal velocity $V_0$. Another lead sphere of mass $8m$ but of the same material will fall through the same liquid with terminal velocity: