出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/06/29 06:38 UTC 版)
Rolling is a combination of rotation (of a radially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that the two are in contact with each other without sliding. This is achieved by a rotational speed at the cylinder or circle of contact which is equal to the translational speed. Rolling of a round object typically requires less energy than sliding, therefore such an object will more easily move, if it experiences a force with a component along the surface, for instance gravity on a tilted surface; wind; pushing; pulling; an engine. Objects with corners, such as dice, roll by successive rotations about the edge or corner which is in contact with the surface.
「rolling」は動詞「roll」の現在分詞です