Which of the following forces does not depend on the velocity: the frictional force between the contact surfaces of two solids or the viscous force?

The maximum static frictional force is

The coefficient of static friction between a wooden block of mass $0.5\, kg$ and a vertical rough wall is $0.2$. The magnitude of the horizontal force that should be applied on the block to keep it adhered to the wall will be $N$ $\left[ g = 10\, m/s^2 \right]$.

$A$ block of mass $M$ is being pulled along a rough horizontal surface. The coefficient of friction between the block and the surface is $\mu$. If another block of mass $M/2$ is placed on the block and it is again pulled on the surface,the coefficient of friction between the block and the surface will be

$A$ pulling force $F$ making an angle $\theta$ with the horizontal is applied on a block of weight $W$ placed on a horizontal table. If the angle of friction is $\alpha$,then the magnitude of the force required to move the body is equal to

As shown in the figure,a force $F$ is applied on a block of mass $\sqrt{3} \ kg$ placed on a rough horizontal surface. The maximum value of $F$ for the block not to move is (Coefficient of static friction between the block and the surface is $\mu = \frac{1}{2 \sqrt{3}}$ and acceleration due to gravity $g = 10 \ m \ s^{-2}$). (in $N$)