libisemishõõrdumiseks

Libisemishõõrdumine, commonly known as sliding friction, is the force that opposes the relative motion of solid surfaces in contact when one surface slides over another. This force always acts in the direction opposite to the motion or the impending motion. It arises from the microscopic irregularities on the surfaces of the materials that interlock and resist movement. Even surfaces that appear smooth to the naked eye have microscopic bumps and valleys that cause this resistance.

The magnitude of the force of sliding friction depends on two primary factors: the nature of the surfaces in contact (their materials and surface texture) and the normal force pressing the surfaces together. The coefficient of friction, a dimensionless quantity, quantifies the frictional properties of the pair of surfaces. A higher coefficient of friction indicates greater resistance to sliding. The force of friction is generally independent of the apparent area of contact between the surfaces, which is a counterintuitive but experimentally verified observation.

Sliding friction is a ubiquitous phenomenon encountered in everyday life, from walking and driving to the operation of mechanical devices. While it can be a source of energy loss through heat generation, it is also essential for many practical applications, such as braking systems and the grip of tires on a road. Reducing unwanted sliding friction often involves lubrication, such as using oil or grease between surfaces, or employing rolling elements like bearings, which replace sliding friction with less resistive rolling friction.