$A$ block of mass $100 \ kg$ slides over a distance of $10 \ m$ on a horizontal surface. If the coefficient of friction between the surfaces is $0.4$,then the work done against friction (in $J$) is:

$A$ horizontal force of $4\,N$ is needed to keep a block of mass $0.5\,kg$ sliding on a horizontal surface with a constant speed. The coefficient of sliding friction must be: $[g = 10\,m/s^2]$

In the given figure,the acceleration of the block of mass $M = \frac{10}{3} \, kg$ is (given $g = 10 \, ms^{-2}$,$\mu = \frac{1}{3}$,$F = 50 \, N$,and $\theta = \sin^{-1}(\frac{3}{5})$):

$A$ bag is gently dropped on a conveyor belt moving at a speed of $2\,m/s$. The coefficient of friction between the conveyor belt and the bag is $0.4$. Initially,the bag slips on the belt before it stops slipping due to friction. The distance travelled by the bag on the belt during the slipping motion is $.....m$. [Take $g=10\,m/s^{-2}$]

$A$ block of mass $10\, kg$ starts sliding on a surface with an initial velocity of $9.8\, m/s$. The coefficient of friction between the surface and the block is $0.5$. The distance covered by the block before coming to rest is: [use $g = 9.8\, m/s^2$].........$m$

$A$ 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 $g = 10 \ m/s^2$):