What is viscosity fluids?

A metal block of base area $0.20 {\mathrm{m}}^2$ is placed on a table, as shown in figure. A liquid film of thickness $0.25 \mathrm{mm}$ is inserted between the block and the table. The block is pushed by a horizontal force of $0.1 \mathrm{N}$ and moves with a constant speed. If the viscosity of the liquid is $5.0\times {10}^{–3} \mathrm{Pl}$, the speed of block is ______ $\times {10}^{-3} \mathrm{m} {\mathrm{s}}^{-1}$.

A steel ball is dropped in a viscous liquid. The distance of the steel ball from the top of the liquid is shown below. The terminal velocity of the ball is closest to

A flat plate of area $10{ \mathrm{cm}}^2$ is separated form a large plate by a layer of Glycerine $1 \mathrm{mm}$ thick. If the coefficient of viscosity of Glycerine is $20$ poise, the force required to keep the plate moving with a velocity of $1 \mathrm{cm} {\mathrm{s}}^{-1}$ is $\underline{ }$
 

The diagram shows a cup of tea seen from above. The tea has been stirred and is now rotating without turbulence. A graph showing the speed v with which the liquid is crossing points at a distance X from O along a radius XO would look like