Which term describes the resistive force that slows a rolling wheel on a surface?

• A. Air Resistance
• B. Mass
• C. Rolling friction
• D. Velocity

Answer: (C)

Rolling friction is the resistive force that slows a rolling wheel on a surface. It occurs because the area where the wheel contacts the ground deforms as the wheel turns, and energy is lost as the wheel and ground recover from that deformation. This energy loss shows up as a small backward force that opposes the motion, slowing the wheel as it rolls. It’s different from air resistance (drag from moving through air), which acts opposite motion in the air; mass is the amount of matter that affects how hard it is to change motion, not a force; and velocity is the speed and direction of motion, not a resisting force. So the term that best describes the slowing force for a rolling wheel on a surface is rolling friction.