Question

If rough surface is polished beyond a certain limit than the magnitude of frictional force will

• A. Nothing can be said.
• B. sometime increases and sometime decreases.
• C. increase.
• D. decrease.

Answer 1

The correct option is C increase.

Friction decreases with smoothness only to a certain degree. When the surfaces are further polished, the Vander Waal forces and electrostatic forces between the atoms of the surfaces increases, this happens because the surfaces come closer when polished.