$A$ block of mass $2 \,kg$ is being pushed against a wall by a force $F=90 \,N$ as shown in the figure. If the coefficient of friction is $0.25$, then the magnitude of acceleration of the block is (Take $g=10 \,ms^{-2}$, $\sin 37^{\circ}=\frac{3}{5}$). (in $\,ms^{-2}$)

$A$ small body slips,subject to the force of friction,from point $A$ to point $B$ along two curved surfaces of equal radius,first along route $1$,then along route $2$. Friction does not depend on the speed and the coefficient of friction on both routes is the same. In which case will the body's speed at $B$ be greater?

$A$ $60 \, kg$ mass is dragged on a horizontal surface by a rope for a distance of $2 \, m$. If the coefficient of friction is $\mu = 0.5$,the angle of the rope with the surface is $60^\circ$,and $g = 9.8 \, m/s^2$,then the work done against friction is ........ $J$.

The coefficient of friction between the block and the surface is $0.03$. Find the acceleration of the system in $m/s^{2}$. $(g = 10\,m/s^{2})$

When we rub our palms,they get heated,but only up to a maximum temperature because:

$A$ block is kept on a rough horizontal surface. The acceleration of the block increases from $6 \ m/s^2$ to $11 \ m/s^2$ when the horizontal force acting on it increases from $20 \ N$ to $30 \ N$. The coefficient of kinetic friction between the block and the surface is (Acceleration due to gravity $g = 10 \ m/s^2$):