When stirring with a spoon is stopped in milk,it comes to rest after some time. Why?

The speed of the water in a river is $V$ near the surface. If the coefficient of viscosity of water is $\eta$ and the depth of the river is $H$,then the shearing stress between the horizontal layers of water is

The relative velocity of two consecutive layers is $8 \ cm/s$. If the perpendicular distance between the layers is $0.1 \ cm$,then the velocity gradient will be ......... $s^{-1}$.

There is a $1\, mm$ thick layer of glycerine between a flat plate of area $100\, cm^2$ and a big plate. If the coefficient of viscosity of glycerine is $1.0\, kg/(m\cdot s)$,then the force required to move the plate with a velocity of $7\, cm/s$ is $.......\, N$.

Why do machine parts become sticky in winter?

The coefficient of viscosity for hot air is