$A$ horizontal force just sufficient to move a body of mass $4 \,kg$ lying on a rough horizontal surface is applied on it. The coefficients of static and kinetic friction are $0.8$ and $0.6$ respectively. If the force continues to act even after the body has started moving, the acceleration of the body is (take $g=10 \,ms^{-2}$). (in $\,ms^{-2}$)

$A$ heavy body of mass $25 \ kg$ is to be dragged along a horizontal plane $\left( \mu = \frac{1}{\sqrt{3}} \right)$. The least force required is ........ $kgf$.

Given below are two statements:
$Statement$ $(I)$: The limiting force of static friction depends on the area of contact and is independent of materials.
$Statement$ $(II)$: The limiting force of kinetic friction is independent of the area of contact and depends on materials.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ force $\vec{F}=\hat{i}+4 \hat{j} \, N$ acts on the block of mass $1 \, kg$ shown in the figure. The coefficient of friction between the block and the surface is $\mu = 0.3$. The force of friction acting on the block is (Take $g = 10 \, m/s^2$)

$A$ force $F = mg$ is acting on a block of mass $m$ at an angle $\theta$ with the horizontal. The coefficient of friction between the block and the surface is $\mu$. The block can be pulled along the surface if:

In the figure shown,a block of weight $10 \, N$ is resting on a horizontal surface. The coefficient of static friction between the block and the surface is ${\mu _s} = 0.4$. $A$ force of $3.5 \, N$ will keep the block in uniform motion,once it has been set in motion. If a horizontal force of $3 \, N$ is applied to the block,then the block will: