Vierintävastusta

Vierintävastusta, also known as rolling resistance, is a force that opposes the motion when an object rolls on a surface. It is a complex phenomenon arising from several factors, primarily the deformation of both the rolling object and the surface it contacts. When a wheel or sphere rolls, it constantly deforms and recovers, leading to energy dissipation, which manifests as rolling resistance. This energy loss means that a continuous force must be applied to maintain a constant velocity.

The primary components contributing to rolling resistance include hysteresis, where the material of the rolling object or surface does not perfectly elastically deform and recover, leading to energy loss. Another significant factor is the adhesion between the rolling object and the surface. Interlocking of surface asperities, or microscopic irregularities, also plays a role. Air resistance, while distinct, can sometimes be confused with or contribute to the overall retarding force experienced during motion.

Rolling resistance is typically measured as a coefficient of rolling resistance, a dimensionless quantity, or as a force. It has a significant impact on the energy efficiency of vehicles, as it is one of the main forces that an engine must overcome. Lower rolling resistance leads to better fuel economy in cars and bicycles. Factors influencing rolling resistance include tire pressure, tire material and construction, load on the wheel, and the type of surface. Smoother and harder surfaces generally exhibit lower rolling resistance than softer or rougher ones.