$A$ small body of mass $500 \,g$ moves on a rough horizontal surface before finally stopping. The initial velocity of the body is $2 \,m/s$ and the coefficient of friction is $0.3$. Find the absolute value of the average power developed by the frictional force during the time of motion. (Take $g = 10 \,m/s^2$) (in $\,W$)

$A$ block of mass $10\, kg$ moving at $10\, m/s$ is released to slide on a rough surface having a coefficient of friction $0.2$. It will stop after travelling a distance of ........ $m$.

$A$ particle of mass $M$ moves along a horizontal $x$-axis from $x=0$ to $x=L$. The coefficient of kinetic friction varies as a function of $x$ as $\mu(x) = \mu_0 - \alpha x$, where $\mu_0$ and $\alpha$ are constants of appropriate dimensions, such that $\mu(L)=0$. The total work done by the frictional force during the motion is $n\mu_0 MgL$, where $g$ is the acceleration due to gravity. The value of $n$ is:

Consider a block and trolley system as shown in the figure. If the coefficient of kinetic friction between the trolley and the surface is $0.04$,the acceleration of the system in $m/s^2$ is (Consider that the string is massless and unstretchable and the pulley is also massless and frictionless):

What is rolling friction? Write the laws of rolling friction. Define the coefficient of rolling friction.

Meena applies the front brakes while riding her bicycle along a flat road. The force that slows her bicycle is provided by the