A block of mass 3kg is at rest on a rough inclined plan as shown in the Figure. The magnitude of net force exerted by the surface on the block will be

Options

A. `15sqrt(3)N`
B. 15 N
C. 10 N
D. 30 N

Answer

D

Explanation

(d) Since, the block is at rest under tow forces
(i) weight of block.
(ii) contact force from the plane (resultant of force of friction and normal reaction).
Contact force should be equal to weight (or 30N) in upward direction. Because under the action of two forces, a body remains in equilibrium when both the forces are equal in magnitude but opposite in direction.