Question

A block is pushed momentarily along a horizontal surface with an initial velocity $v$. If $\mu$ is the coefficient of kinetic friction between block and surface is $\mu$, the block will come to rest after a time.

• A. $\frac{v}{\mu g}$
• B. $\frac{\mu g}{v}$
• C. $\frac{g}{v}$
• D. $\frac{v}{g}$

Answer 1

The correct option is A $\frac{v}{\mu g}$

If the coefficient of friction is $\mu$

than acceleration due to friction is $a=f/m=-\mu mg/m=-\mu g$

apply first equation of motion

$v=u+at$

$0=v-\mu g\times t$

$t=\frac{v}{\mu g}$