A medicine ball rolling across the floor is an example of which type of friction?

The correct answer identifies the type of friction acting on a medicine ball rolling across the floor as rolling friction. This type of friction occurs when an object rolls over a surface, and it is different from sliding and static friction.

In rolling friction, the contact area between the object (in this case, the medicine ball) and the surface is relatively small, which reduces the resistance encountered as the ball rolls compared to sliding friction, where one surface slides over another. This concept is crucial because it helps explain why rolling objects, like balls or wheels, require less force to maintain motion than sliding objects do.

Static friction would apply if the medicine ball were at rest and resisting the initiation of movement. Fluid friction pertains to objects moving through a fluid, such as water or air, which does not apply to a rolling ball on a solid surface. Understanding these distinctions is vital for comprehending dynamics in exercise and sports sciences, as it informs training techniques and equipment choices.