Question

Example 2. A block of mass 3 kg is lying on the
floor. The coefficient of friction is 0-4. A force of
3N is applied on the block as shown in fig. Calcu-
late the force of friction between the block and the
floor.​

Answer 1

Explanation:

block is placed on the horizontal plane, so mg=N

also maximum friction force is μ.N=0.4×3×10=12N.

but friction force acts only if there is a tendency of motion. so friction force will be equal to force applied until it reaches its maximum value. After that limiting friction will act and body will start moving.

So 3.5<12, hence friction acting is 3.5N and body will not move.