Question

Which of the following statement about friction is wrong?

• A. Frictional force can accelerate a body.
• B. Kinetic friction is always greater than rolling friction.
• C. Frictional force can be reduced to zero.
• D. Frictional force is proportional to the area of contact between the surfaces.

Answer 1

Answer: (D)

We know frictional force depends only on friction co-efficient and normal force.
Friction co-efficient depends on nature of surface of contact not area of contact..
Normal reaction is also independent of area of contact. So, we can say that friction force is independent of area of contact. So "Frictional force is proportional to the area of contact between the surfaces" is wrong statement.