Question

A block of 1 kg is stopped against a wall by applying
a force F perpendicular to the wall. If u = 0.2 then
minimum value of F will be
(1) 980 N (2)49 N (3) 98 N (4400 N​

Answer 1

answer : 49 N

explanation : friction is the force resisting the relative motion of two solid surface. see figure, block has tendency to move downward with respect to wall.so, friction force must be applied upward as shown in figure.

a force F is applied perpendicularly on the block. Let normal reaction acts between the block and wall is N.

at equilibrium,

F = N.....(1)

and fr = mg = 1kg × 9.8 m/s² = 9.8N

as we know, friction = μN, where μ is coefficient of friction.

so, 9.8 = 0.2 × N

or, N = 9.8/0.2 = 49

from equation (1),

F = 49N

hence, minimum value of F will be 49N

Answer 2

Answer:

49

Explanation:

its is as it's above given