$A$ spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball $(v)$ as a function of time $(t)$ is

Two rain drops of same radius $r$ falling with terminal velocity $V$ merge and form a bigger drop with radius $R$. The terminal velocity of the bigger drop is:

If the average terminal velocity of a rain drop is $2 \,m/s$, then the energy transferred by rain to each square metre of the surface at a place which receives $100 \,cm$ of rain in a year is

The velocity of a small ball of mass $0.3 \, g$ and density $8 \, g/cc$ when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is $1.3 \, g/cc$,then the value of the viscous force acting on the ball will be $x \times 10^{-4} \, N$. The value of $x$ is [use $g = 10 \, m/s^2$]. (in $.125$)

$A$ ball rises to the surface of a liquid with constant velocity. The density of the liquid is four times the density of the material of the ball. The viscous force of the liquid on the rising ball is greater than the weight of the ball by a factor of

$A$ solid ball of volume $V$ is dropped in a viscous liquid. It experiences a viscous force $F$. If a solid ball of volume $2V$ of the same material is dropped in the same fluid,then the viscous force acting on it will be