Question

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

Answer 1

answer : 30N

explanation : A block of mass ,m = 3kg is at rest on a rough inclined plane as shown in figure.

according to Newton's 3rd law,

action and reaction are of equal in magnitude and directed in opposite directions.

here, a block is placed on the inclined plane. so, weight of block exerted force on inclined plane to move downward. but inclined plane restricts the block to move downward.

so, weight of block = net force applied by the surface on the block

or, 3kg × 10m/s² = 30N = net force applied by the surface on the block.

[ here we have assumed that roughness of inclined plane is very high so that block doesn't slide downward ].

Answer 2

weight of block = net force applied by the surface

Mg = F

$3 \times 10m {s}^{2}$

30N....