$A$ block of mass $4 \text{ kg}$ is placed on a horizontal surface having coefficients of static and kinetic friction as $0.5$ and $0.4$ respectively. If a force of $4 \text{ N}$ is applied parallel to the horizontal surface, then the force of friction acting on the body will be $\left[g = 10 \text{ m/s}^2\right]$ (in $\text{ N}$)

$A$ block of mass $M$ rests on a rough horizontal table. $A$ steadily increasing horizontal force is applied such that the block starts to slide on the table without toppling. The force is continued even after sliding has started. Assume the coefficients of static and kinetic friction between the table and the block to be equal. The correct representation of the variation of the frictional force $f$,exerted by the table on the block with time $t$ is given by

As shown in the figure, a block of mass $10 \ kg$ lying on a horizontal surface is pulled by a force $F$ acting at an angle $30^{\circ}$ with the horizontal. For $\mu_{s} = 0.25$, the block will just start to move for the value of $F$: [Given $g = 10 \ ms^{-2}$] (in $N$)

$A$ uniform chain of $6 \, m$ length is placed on a table such that a part of its length is hanging over the edge of the table. The system is at rest. The coefficient of static friction between the chain and the surface of the table is $0.5$. The maximum length of the chain hanging from the table is.......$m.$

Write the unit of the coefficient of static friction.

If a pushing force making an angle $\alpha$ with the horizontal is applied on a block of mass $m$ placed on a horizontal table and the angle of friction is $\beta$,then the minimum magnitude of the force required to move the block is