Water in a river $20 \ m$ deep is flowing at a speed of $10 \ ms^{-1}$. The shearing stress between the horizontal layers of water in the river in $Nm^{-2}$ is (Coefficient of viscosity of water $= 10^{-3} \ SI \ units$)

$A$ metal plate of area $10^{-2} \,m^2$ rests on a layer of castor oil, $2 \times 10^{-3} \,m$ thick, whose coefficient of viscosity is $1.55 \,Ns\, m^{-2}$. The approximate horizontal force required to move the plate with a uniform speed of $3 \times 10^{-2} \,ms^{-1}$ is (in $N$)

$A$ flat plate of area $10 \, cm^2$ is separated from a large plate by a layer of glycerine $1 \, mm$ thick. If the coefficient of viscosity of glycerine is $20 \, \text{poise}$, the force required to keep the plate moving with a velocity of $1 \, cm/s$ is .......... $dyne$.

$A$ river $10\,m$ deep is flowing at $5\,m/s$. The shearing stress between horizontal layers of the river is :- $(\eta = 10^{-3}\,SI\,unit)$

$A$ cubical block of side $a$ and density $\rho$ slides over a fixed inclined plane with constant velocity $v$. There is a thin film of viscous fluid of thickness $t$ between the plane and the block. If the angle of inclination is $37^{\circ}$,then the coefficient of viscosity of the thin film will be:

$A$ square plate of side $0.1 \, m$ moves over another plate with a velocity of $0.1 \, m/s$ in a liquid of viscosity $0.01 \, poise$. If the viscous force acting is $0.002 \, N$,what is the distance between the two plates (in $, m$)?