$A$ horizontal force of $40\,N$ is applied to a $5\,kg$ block which is at rest on a horizontal surface. If the coefficient of kinetic friction is $0.4$,then the acceleration of the block is ........ $m/s^2$ $(g = 10\,m/s^2)$.

$A$ block of mass $2 \ kg$ is placed on a rough horizontal surface. If a horizontal force of $20 \ N$ acting on the block produces an acceleration of $7 \ m \ s^{-2}$ in it,then the coefficient of kinetic friction between the block and the surface is $(g = 10 \ m \ s^{-2})$.

$A$ block of mass $m=2 \ kg$ is initially at rest on a horizontal surface. $A$ horizontal force $F_1=(6 \ N) \hat{i}$ and a vertical force $F_2=(10 \ N) \hat{j}$ are then applied to the block. The coefficients of static friction and kinetic friction for the block and the surface are $0.4$ and $0.25$, respectively. The magnitude of the frictional force acting on the block is (assume $g=10 \ m/s^2$): (in $N$)

$A$ car is moving on a straight horizontal road with a speed $v.$ If the coefficient of friction between the tyres and the road is $\mu ,$ the shortest distance in which the car can be stopped is

It is easier to roll a barrel than to pull it along the road. This statement is

$A$ block of mass $5\,kg$ is placed at rest on a table with a rough surface. If a force of $30\,N$ is applied parallel to the surface of the table,the block slides through a distance of $50\,m$ in $10\,s$. Calculate the coefficient of kinetic friction. (Given: $g = 10\,m/s^2$)