Question

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

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

Answer 1

Answer: (A)

Block B will come to rest, it force applied to it will vanish due to frictional force acting between block B and surface $ie,$
$force \, applied=frictional \, force$
$ie, \, \, \mu \, mg=ma$
$or \, \, \, \mu \, mg=m\left(\frac{v}{t}\right)$
$or \, \, t=\frac{v}{\mu \, g}$