Question

Friction is increased if

• A. an oil is sprayed
• B. the surfaces are made wet
• C. the surfaces are made dry
• D. the surfaces are polished

Answer 1

The correct option is C

the surfaces are made dry

Friction is a force that resists the motion of one object against another.

Friction can be increased by the following methods:

1. Friction can be increased by increasing the roughness of the surfaces in contact.
2. The treading of shoes and tires is done to increase friction
3. Friction occurs between two surfaces when the surfaces are not smooth. On a molecular scale, materials have bumps and ridges, which get stuck on the bumps and ridges of the other material.
4. Hence dry surfaces have more friction whereas liquids, such as water, act as a lubricant and fill these gaps and reduce friction

Hence, Friction is increased if the surfaces are made dry. So the correct option is C