Which type of friction occurs when surfaces slide past one another?

Which type of friction occurs when surfaces slide past one another?

• A. Kinetic friction.
• B. Static friction.
• C. Rolling friction.
• D. Air resistance.

Answer: (A)

When two surfaces slide past each other, the resisting force you’re dealing with is kinetic friction. It acts opposite the direction of motion and arises only after sliding begins, with its magnitude given by μ_k times the normal force. This type of friction is usually less than static friction, which must be overcome to start the sliding. The other options describe different resistive forces: static friction keeps surfaces from moving relative to each other, rolling friction occurs when something rolls, and air resistance comes from moving through a fluid like air, not from contact between surfaces. So for sliding, kinetic friction is the correct concept.

When two surfaces slide past each other, the resisting force you’re dealing with is kinetic friction. It acts opposite the direction of motion and arises only after sliding begins, with its magnitude given by μ_k times the normal force. This type of friction is usually less than static friction, which must be overcome to start the sliding. The other options describe different resistive forces: static friction keeps surfaces from moving relative to each other, rolling friction occurs when something rolls, and air resistance comes from moving through a fluid like air, not from contact between surfaces. So for sliding, kinetic friction is the correct concept.