Which of the following is NOT a listed type of friction?

Which of the following is NOT a listed type of friction?

• A. Kinetic
• B. Static
• C. Rolling
• D. Viscous

Answer: (D)

The main idea is how friction is categorized for everyday problems. In most introductory discussions, friction is described in three common forms: static friction, which prevents motion up to a limit; kinetic (sliding) friction, which opposes motion once surfaces slide past each other; and rolling friction, which resists the rolling of a wheel or cylinder due to deformation and other small losses. Viscous friction, on the other hand, comes from a fluid’s resistance to motion—like air or oil moving around an object. That isn’t a friction between solid surfaces at a contact patch, so it isn’t listed among the standard friction types. Hence, viscous is the one that doesn’t fit with the typical trio of static, kinetic, and rolling friction.

The main idea is how friction is categorized for everyday problems. In most introductory discussions, friction is described in three common forms: static friction, which prevents motion up to a limit; kinetic (sliding) friction, which opposes motion once surfaces slide past each other; and rolling friction, which resists the rolling of a wheel or cylinder due to deformation and other small losses. Viscous friction, on the other hand, comes from a fluid’s resistance to motion—like air or oil moving around an object. That isn’t a friction between solid surfaces at a contact patch, so it isn’t listed among the standard friction types. Hence, viscous is the one that doesn’t fit with the typical trio of static, kinetic, and rolling friction.