Question

A body of mass 2 kg is kept by pressing to a vertical wall by a force of 100 N. the coefficient of friction between wall and body is 0.3. then the frictional force is equal to:

• A. 6 N
• B. 20 N
• C. 600 N
• D. 700 N

Answer 1

The correct option is B 20 N

Static friction is the force that keeps the object at rest. It must be overcome to start moving the object. If a small amount of force is applied to an object, the static friction has an equal magnitude in the opposite direction.

Coefficient of friction $\left(\mu \right)=0.3$

Normal force$=100N$

So, $f_{max}\left(Maximimfrictionforce\right)=100\times 0.3=30N$

Force trying to produce motion $=mg=2\times 10=20N$

So, frictional force $=20N$