Which force slows down rolling objects?

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

Answer: (A)

When something rolls, the force that opposes its motion is rolling friction. As the wheel or ball makes contact with the surface, tiny deformations occur in both the object and the ground. The energy lost to these deformations (and heat) shows up as a resistive force that slows the rolling object down. That’s why a rolling wheel on a surface gradually loses speed even if nothing is actively pushing it.

Mass isn’t a force; it’s the amount of matter in the object and it influences how hard it is to change the motion, not the slowing force itself. Air resistance acts in the air and can slow moving objects, but for a rolling object on a surface, rolling friction is the primary resistance. Velocity is speed, not a force, so it doesn’t explain a slowing force on its own.