question_answer

A body is moving along a rough horizontal surface with an initial velocity 6m/s. If the body comes to rest after travelling a distance 9m. Then the coefficient of sliding friction will be:

A) 0.4                   

B) 0.2      

C) 0.6                               

D) 0.8

Correct Answer: B

Solution :

At equilibrium \[{{\operatorname{Ma}}_{o}} = \mu Mg\] \[{{a}_{o}} = \mu g\] \[{{\operatorname{v}}^{2}}-{{\operatorname{u}}^{2}}=2\operatorname{aS}\] \[0-{{\left( 6 \right)}^{2}}=-2\mu \operatorname{g}\times 9\][- sign for retardation] \[\mu =0.2\]