Question

A block of mass 4 kg rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is: $(g=9.8m/s^2)$

• A. 19.6
• B.
• C.
• D. 0.7 ×9.8

Answer 1

The correct option is A

19.6

Since, $\mu mgcos\theta >mgsin\theta$

$\therefore \text{F}orceoffrictionisf=mgsin\theta =4\times 9.8\times sin{30}^0=4\times 9.8\times \frac{1}{2}=19.6N$