The speed of a ball of radius $2 \,cm$ in a viscous liquid is $20 \,cm / s$. What will be the speed of a ball of radius $1 \,cm$ in the same liquid (in $\,cm / s$)?

If the terminal velocity of a metal sphere of mass $8 \ g$ falling through a liquid is $3 \ cm s^{-1}$,then the terminal velocity of another sphere of mass $64 \ g$ made of the same metal falling through the same liquid is (in $cm s^{-1}$)

$A$ small drop of water falls from rest through a large height $h$ in air; the final velocity is

Sixty-four rain drops of radius $1 \ mm$ each,falling down with a terminal velocity of $10 \ cm/s$,coalesce to form a bigger drop. The terminal velocity of the bigger drop is . . . . . . $cm/s$.

$A$ sphere of radius $r$ and density $\rho$ is dropped from a height $h$. When it falls into water,it attains a terminal velocity. If the coefficient of viscosity of water is $\eta$,then $h =$

The terminal velocity of a small sphere of radius $a$ in a viscous liquid is proportional to