$A$ Newtonian fluid fills the clearance between a shaft and a sleeve. When a force of $800$ $N$ is applied to the shaft,parallel to the sleeve,the shaft attains a speed of $1.5$ $cm/s$. If a force of $2.4$ $kN$ is applied instead,the shaft would move with a speed of ......... $cm/s$.

The velocity of water in a river is $18\, km/h$ near the surface. If the river is $5\, m$ deep,find the shearing stress between the horizontal layers of water. The coefficient of viscosity of water is $\eta = 10^{-2}\, \text{poise}$.

$A$ metal block of base area $0.20\,m^2$ is placed on a table,as shown in the figure. $A$ liquid film of thickness $0.25\,mm$ is inserted between the block and the table. The block is pushed by a horizontal force of $0.1\,N$ and moves with a constant speed. If the viscosity of the liquid is $5.0 \times 10^{-3} \,Pa-s$,the speed of the block is $.........\times 10^{-3}\,m/s$.

Water is flowing on a horizontal fixed surface,such that its flow velocity varies with $y$ (vertical direction) as $v = k \left( \frac{2y^2}{a^2} - \frac{y^3}{a^3} \right)$. If the coefficient of viscosity for water is $\eta$,what will be the shear stress between the layers of water at $y = a$?

$A$ metal block of base area $0.2\; m^{2}$ is connected to a $0.02\; kg$ mass via a string that passes over an ideal pulley as shown in the figure. $A$ liquid film of thickness $0.6\; mm$ is placed between the block and the table. When released,the block moves to the right with a constant speed of $0.17\; m/s$. The coefficient of viscosity of the liquid is:

Write one practical use of viscosity.