How is rolling friction caused?

Rolling friction is caused by the interaction between two surfaces in contact, such as a wheel rolling along a surface. When a wheel is moving, only a small portion of its surface area comes into contact with the ground at any given time.

This means that the force of friction acting on the wheel is spread out over a larger area, reducing the overall force required to move the wheel.

The key factors that affect rolling friction are the size and shape of the wheel, as well as the nature of the surface it is rolling on—wheels with a more considerable radius experience less rolling friction than wheels with a smaller radius.

This is because the larger radius results in a smaller contact area between the wheel and the ground, reducing the force of friction.

The shape of the wheel also plays a role in rolling friction. Wheels with a smooth, round shape experience less rolling friction than those with a more angular shape. This is because the smooth, round shape allows the wheel to roll more easily over any bumps or imperfections on the surface it is rolling on.

The nature of the surface also affects rolling friction. A smooth, flat surface like a polished floor or a well-maintained road will create less rolling friction than a rough, uneven surface like a gravel road or a bumpy sidewalk.

This is because the rough surface creates a more frictional force by interlocking with the surface of the wheel.