Question

The force of friction is ....................... the normal reaction between the surfaces.

• A. Inversely propotional to
• B. directly propotional to
• C. propotional to the square of
• D. independent of

Answer 1

The correct option is B directly propotional to

Friction acts between two surfaces and is tangential to both the surfaces. This tangential interaction (friction force) is proportional to the normal force between two surfaces as per by emperical law.

The equation is : F${}_n$ = F${}_g$Cos$\theta$

Hence the force of friction is directly proportional to normal reaction between the surfaces.