Question

Which of the following factors do not affect friction?

• A. Thrust
• B. Roughness of surface
• C. Smoothness of surface
• D. Amount of surface area in contact between the moving bodies
  

Answer 1

The correct option is D Amount of surface area in contact between the moving bodies


Friction increases with increase in thrust because when thrust increases interlocking and adhesion also increases.
When the surface is rough, friction will be more and when the surface is smooth, friction will be less.
Therefore, we can say that friction depends only on the nature of the surfaces ( roughness or smoothness) and the thrust applied, but not on the amount of surface area in contact.