B M Sharma Solutions for Chapter: Surface Tension and Viscosity, Exercise 5: CONCEPT APPLICATION EXERCISE

A viscous fluid is flowing through two horizontal pipes. The pressure difference $P_2-P_1$ between the ends of each pipe is the same. The pipes have the same radius, although one is twice as long as the other. How does the volume flow rate $Q_B$ in the longer pipe compare with the rate $Q_A$ in the shorter pipe?

A man is rowing a boat with a constant velocity ' $v_0$ ' in a river. The contact area of boat is 'A' and coefficient of viscosity is $\eta$. The depth of river is ' $D$'. Find the force required to row the boat.

A cubical block (of side $2 \mathrm{m}$) of mass $20 \mathrm{kg}$ slides on inclined plane lubricated with the oil of viscosity $\eta ={10}^{-1} \mathrm{poise}$  with constant velocity of $10{ \mathrm{ms}}^{-1}$. Find out the thickness of the layer of liquid (take $g=10{ \mathrm{ms}}^{-2}$ ).

A drop of water of radius $0.0015 \mathrm{mm}$ is falling in air. If the coefficient of viscosity of air is $1.8\times {10}^{-5} \mathrm{kg} {\mathrm{m}}^{-1} {\mathrm{s}}^{-1}$. what will be the terminal velocity of the drop? Density of water $=1.0\times {10}^3 \mathrm{kg} {\mathrm{m}}^{-3}$ and $g=9.8 \mathrm{N} {\mathrm{kg}}^{-1}$. Density of air can be neglected.
 

A metallic sphere of radius $1.0\times {10}^{-3} \mathrm{m}$ and density $1.0\times {10}^4 \mathrm{kg} {\mathrm{m}}^{-3}$  enters a tank of water, after a free fall through a distance of $h$ in the earth's gravitational field. If its velocity remains unchanged after entering water, determine the value of $h$. Given$‐$ coefficient of viscosity of water is $1.0\times {10}^{-3} \mathrm{N} \mathrm{s} {\mathrm{m}}^{-2}$, $g=9.8 \mathrm{m} {\mathrm{s}}^{-2}$ and density of water is $1.0\times {10}^3 \mathrm{kg} {\mathrm{m}}^{-3}$.

Find the minimum force required to drag a hard polythene plate of area $2{ m}^2$ on a thin film of oil of thickness $0.25 cm$ and $\eta =15$ poise. Assume the speed of the plate is $10 cm{ s}^{-1}$.

A force of $3.14 \mathrm{N}$ is required to drag a sphere of radius $4 \mathrm{cm}$ with a speed of $5 {\mathrm{ms}}^{-1}$ in a medium in gravity free space. Find the coefficient of the viscosity of the medium.

In a hospital, a patient receives a $500{ \mathrm{cm}}^3$ blood transfusion through a needle with a length of $5 \mathrm{cm}$ and inner radius of $0.03 \mathrm{cm}$. If the blood bag is kept $85 \mathrm{cm}$ above the needle, how long the transfusion takes place? Given that the viscosity of blood is $0.017 \mathrm{poise}$  and the density of blood is $1.02 \mathrm{g}{ \mathrm{cm}}^{-3}$.