Viscosity

A spherical ball of radius $\text{1}\times 10^{-4} \mathrm{m}$ and density $104 \mathrm{kg} {\mathrm{m}}^{-3}$^​ falls freely under gravity through a distance $h$ before entering a tank of water. If after entering the water the velocity of the ball does not change, find $h$. The viscosity of water is $9.8\times 10^{-6} {\mathrm{Nsm}}^{-2}$.

The terminal velocity of copper ball of radius$2 \mathrm{mm}$ falling through a tank of oil at $20 °\mathrm{C}$  is $6.5 \mathrm{cm} {\mathrm{s}}^{-1}$. If viscosity of the oil at $20 °\mathrm{C}$ is $9.9\times {10}^{-1} \mathrm{kg} {\mathrm{m}}^{-1} {\mathrm{s}}^{-1 }$and density of copper is $8.9\times {10}^3 \mathrm{kg} {\mathrm{m}}^{-3}.$ Then density of the oil will be

Eight equal drops of water are falling through air with a steady speed of $10 \mathrm{cm} {\mathrm{s}}^{-1}$. If the drops coalesce, the new velocity is:-

An air bubble of diameter $6 \mathrm{mm}$ rises steadily through a solution of density $1750 \mathrm{kg} {\mathrm{m}}^{-3}$ at the rate of $0.35 \mathrm{cm} {\mathrm{s}}^{-1}$. The co-efficient of viscosity of the solution (neglect density of air) is ________ Pas (given, $\mathrm{g} =10 \mathrm{m} {\mathrm{s}}^{-2}$).

A ball of mass $m$ and radius $r$ and density $\rho$ is dropped in a liquid of density ${\rho }_0$. After moving for sometime, the speed of the ball becomes constant and equal to $v_0$. The coefficient of viscosity of the liquid is

What is the dimension of rate of flow?

A force $\mathrm{F}={\mathrm{Be}}^{\mathrm{Ct}}$ acts on a particle whose mass is $\mathrm{m}$ and whose velocity is $0$ at $t=0$. It's terminal velocity (velocity after a long time) is:

The velocity of a small ball of mass $m$ and density $d_1$, when dropped in a container filled with glycerine, becomes constant after some time. If the density of glycerine is $d_2$, then the viscous force acting on the ball, will be

The velocity of upper layer of water in a river is $36 \mathrm{km} {\mathrm{h}}^{-1}$. Shearing stress between horizontal layers of water is ${10}^{-3} \mathrm{N} {\mathrm{m}}^{-2}$. Depth of the river is _____ $\mathrm{m}$. (Co-efficient of viscosity of water is ${10}^{-2} \mathrm{Pa} \mathrm{s}$)

A water drop of radius $1\mu \mathrm{m}$ falls in a situation where the effect of buoyant force is negligible. Co-efficient of viscosity of air is $1.8\times {10}^{-5} \mathrm{N} \mathrm{s} {\mathrm{m}}^{-2}$ and its density is negligible as compared to that of water ${10}^6 \mathrm{g} {\mathrm{m}}^{-3}$. Terminal velocity of the water drop is

(Take acceleration due to gravity $=10{ \mathrm{m} \mathrm{s}}^{-2}$)

The terminal velocity $\left(v_t\right)$ of the spherical rain drop depends on the radius $\left(r\right)$ of the spherical rain drop as 

A piece of iron bob is dropped in a very long column of water. What type of motion will be experienced by the bob near the bottom of the water column ?

What is the constant force $F$ required to pull the plate of area A parallel to wall with constant velocity $V_0$ in the given figure. ( $\eta =$ coefficient of viscosity.)

A pump can push a viscous oil through a long straight pipe of length $l$ with the flow rate of $Q$. Now a part of the middle section of the pipe is replaced by a ring-shaped section of mean radius $R$ having the same internal cross-section as that of the pipe. If the same pump is used to push oil through this modified pipe then what will be the flow rate.

Two identical balloons, filled with gases of different densities $0.9 \mathrm{kg} {\mathrm{m}}^{-3}$ and $1.1\mathrm{kg} {\mathrm{m}}^{-3}$ are released from an airplane into the atmosphere (density $=1 \mathrm{kg} {\mathrm{m}}^{-3}$ ). Find the speed of lighter balloon as seen by heavier balloon after a long time.

Given: radius of the balloons $r=3 \mathrm{cm}$
Coefficient of viscosity $\eta ={10}^{-5} \mathrm{Pa}-\mathrm{s}$
$g=10 {\mathrm{ms}}^{-2}$

A plastic circular disc of radius $10 \mathrm{cm}$ is placed on a thin oil film of thickness $2 \mathrm{mm}$, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity $8 \mathrm{rad} {\mathrm{s}}^{-1}$ is $\frac{\pi }{K} \mathrm{N} \mathrm{m}$ (coefficient of viscosity of the oil is $1.0 \mathrm{kg} {\mathrm{m}}^{-1} {\mathrm{s}}^{-1}$). Then find the value of $K$.

Does a parachute descend slowly?

A layer of oil $1.5 \mathrm{mm}$ thick is placed between two microscope slides. A force of $5.5\times {10}^{-4} \mathrm{N}$ is required to glide one slide over the other at a speed of $1 \mathrm{cm} {\mathrm{s}}^{-1}$. If the coefficient of viscosity of the oil is $0.138 \mathrm{N} \mathrm{s} {\mathrm{m}}^{-2}$, then their contact area is _____.

The possible CGS units of coefficient of viscosity is 

Which of the following are the possible S.I. units of coefficient of viscosity?