Question

A body rolled on a surface with speed of$10{ms}^{-1}$ comes to rest after covering a distance of $50m$. Find the coefficient of friction. Take $g=10{ms}^{-2}$.

Answer 1

Initial kinetic energy was $\frac{1}{2}m{v}^2=\frac{1}{2}\times m\times 100=50m$, $m$ is mass of the body.

as it comes to rest so wok done is $loss$ in $kinetic$ energy i.e. $W=50m$

Maximum kinetic friction is $F=\mu mg$ so work done $W=F\times distance=\mu mg\times 50meter=500m\mu$

Equating both values of $W$ we get $500m\mu =50m$

so $\mu =0.10$