Question

A block of mass $2\text{kg}$ rests on a rough inclined plane making an angle of ${30}^{\circ }$ with the horizontal. The coefficient of static friction between the block and the plane is $0.7$. The frictional force on the block is

• A. $9.8\text{N}$
• B. $0.7\times 9.8\times \sqrt{3}\text{N}$
• C. $9.8\times \sqrt{3}\text{N}$
• D. $0.7\times 9.8\text{N}$

Answer 1

The correct option is A $9.8\text{N}$

Since the block is at rest, therefore force of friction
$=mg\sin \theta =2\times 9.8\times \sin {30}^{\circ }=9.8\text{N}$