転がり運動

right|thumb|The animation illustrates rolling motion of a wheel as a Superposition principle|superposition of two motions: translation with respect to the surface, and rotation around its own axis. Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.