Question

A block of mass $2kg$ is resting on a rough inclined plane of inclination ${30}^{\circ }$. If the coefficient of friction is $0.8$, the resultant contact force between incline and the block is $(g=10m{s}^{-2})$

• A. $20N$
• B. $10N$
• C. $10\sqrt{3}N$
• D. None of these

Answer 1

The correct option is A $20N$

As the block is at rest, the net contact force on the block i.e. resultant of friction and normal reaction must balance the weight of the block. Hence $R=mg=20N$