$A$ block of weight $W$ is held against a vertical wall by applying a horizontal force $F$. The minimum value of $F$ needed to hold the block is $[\mu < 1]$.

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 $N$)

The coefficient of friction $\mu$ and the angle of friction $\lambda$ are related as

What is friction? What is impending motion?

$A$ force of $19.6\, N$ when applied parallel to the surface just moves a body of mass $10\, kg$ kept on a horizontal surface. If a $5\, kg$ mass is kept on the first mass,the force applied parallel to the surface to just move the combined body is........ $N.$

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 $N$)