The terminal velocity of a sphere of radius $3 \ mm$ falling in a viscous liquid is $10 \ cm/s$. The terminal velocity of a ball of radius $6 \ mm$ of the same material falling in the same liquid will be $...... \ cm/s$.

The terminal velocity of a copper ball of radius $5\,mm$ falling through a tank of oil at room temperature is $10\,cm\,s^{-1}$. If the viscosity of oil at room temperature is $0.9\,kg\,m^{-1}s^{-1}$,the viscous drag force is:

Suppose the average mass of raindrops is $3.0 \times 10^{-5} \ kg$ and their average terminal velocity is $9 \ m/s$. Calculate the energy transferred by rain to each square metre of the surface at a place which receives $100 \ cm$ of rain in a year.

$A$ metal sphere of radius $R$ and density $\varrho_{1}$ moves with terminal velocity $v_{1}$ through a liquid of density $\sigma$. Another sphere of the same radius but of density $\varrho_{2}$ moves through the same liquid. Its terminal velocity will be:

When milk is shaken in a glass,it becomes still after some time. Why?

Eight identical small drops of water are falling down vertically through a medium,each with terminal velocity $v$. If they combine to form a single drop,then its terminal velocity will be (in $v$)