The coefficient of static friction,$\mu_s$,between block $A$ of mass $2\, kg$ and the table as shown in the figure is $0.2$. Find the maximum mass value of block $B$ in $kg$ so that the two blocks do not move. The string and the pulley are assumed to be smooth and massless. $(g = 10\, m/s^2)$

$A$ man walks over a rough surface; the angle between the force of friction and the instantaneous velocity of the person is

What is friction? What is impending motion?

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:

The blocks $A$ and $B$ are arranged as shown in the figure. The pulley is frictionless. The mass of $A$ is $10 \, kg$. The coefficient of friction of $A$ with the horizontal surface is $0.20$. The minimum mass of $B$ to start the motion will be...... $kg$.

What is the maximum acceleration of a train such that a $50 \ kg$ box lying on its floor remains stationary (in $m \ s^{-2}$)? (Given: Coefficient of static friction between the box and the train's floor is $0.3$ and $g = 10 \ m \ s^{-2}$)