In a laminar flow,the velocity of the liquid in contact with the walls of the tube is:

$A$ 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. Then the coefficient of viscosity of the thin film will be

Why do machine parts become sticky in winter?

Define velocity gradient and give its unit. Also,write the dimensional formula of the velocity gradient.

$A$ 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:

$A$ good lubricant should have