Viscous drag force depends on ...........

What is viscosity? What is the cause of it?

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

Hot liquids flow more easily than cold liquids. Give the reason.

$A$ plastic circular disc of radius $R$ is placed on a thin oil film,spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to

$A$ 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 $N$)