Question

Which of the following will have the highest amount of friction between them?

• A. Two smooth plates
• B. Two rough plates with oil in between them
• C. Two rough plates
• D. Two rough plates pressed against each other

Answer 1

The correct option is D Two rough plates pressed against each other

Friction depends on the interlocking capacity of the two surfaces. So, two rough plates will have larger interlockings between them as compared to smooth plates.
However, if the surfaces are pressed against each other, the interlockings would increase further. This will increase friction between them. So, rough plates that are pressed hard will have the highest amount of friction.