Two raindrops reach the earth with different terminal velocities having the ratio $9: 4$. The ratio of their volumes is

$A$ small ball of mass $M$ and density $\rho$ is dropped in a viscous liquid of density $\rho_0$. After some time,the ball falls with a constant velocity. What is the viscous force on the ball?

If a ball of steel (density $\rho = 7.8 \; g \cdot cm^{-3}$) attains a terminal velocity of $10 \; cm \cdot s^{-1}$ when falling in a tank of water (coefficient of viscosity $\eta_{\text{water}} = 8.5 \times 10^{-4} \; Pa \cdot s$),then its terminal velocity in glycerine (density $\rho_{\text{gly}} = 1.2 \; g \cdot cm^{-3}$,coefficient of viscosity $\eta_{\text{gly}} = 13.2 \; Pa \cdot s$) would be nearly:

Which of the following diagrams correctly shows the relation between the terminal velocity $v_{T}$ of a spherical body falling in a liquid and viscosity $\eta$ of the liquid?

$A$ small ball of mass $M$,radius $R$ and density $\rho$ moves with terminal velocity through a container filled with glycerine of density $\sigma$. The viscous force acting on the ball is ($g=$ gravitational acceleration).

An air bubble of radius $r$ rises steadily through a liquid of density $\rho$ with velocity $v$. The coefficient of viscosity of the liquid is: