Veerehõõrdjõud

Veerehõõrdjõud is the Estonian term for rolling friction. It is a type of friction that occurs when a round object, such as a wheel or ball, rolls over a surface. Unlike sliding friction, which opposes the sliding motion between two surfaces in contact, rolling friction is typically much smaller and arises from a combination of factors.

The primary causes of rolling friction include the deformation of the rolling object and the surface it rolls on. When a wheel rolls, the surface beneath it and the wheel itself are slightly compressed or deformed. This deformation creates a slight uphill resistance for the wheel to overcome as it moves forward. Energy is lost due to this deformation and subsequent recovery, which manifests as rolling friction.

Another contributing factor is adhesion between the surfaces, although this is generally less significant than deformation. Tiny imperfections on both the wheel and the surface can temporarily stick together as the wheel rolls, requiring a small amount of force to break these bonds. Additionally, if the surface is not perfectly smooth, the rolling object might encounter slight bumps or irregularities, leading to additional resistance.

Rolling friction is crucial in many everyday applications. It is what allows vehicles to move efficiently. Engineers aim to minimize rolling friction in applications like bicycle tires and ball bearings to reduce energy loss and improve performance. Conversely, in some situations, like the brakes on a car or the treads of hiking boots, a higher degree of friction, including rolling resistance, is intentionally designed to enhance grip and control. The magnitude of rolling friction depends on the materials of the object and surface, their shapes, and the applied load.