The body without deformation is called a rigid body. 铁石心肠 不可塑造 Its motion includes usually two types: (1) translation(平动); (2) rotation(转动)。 Examples: dancing, stang, motion of Earth, motion of electron in the atom worldThe body without deformation is called a rigid body. (1) translation（平动）; (2) rotation（转动）。 Examples: dancing, skating, motion of Earth, motion of electron in the atom world,……. Its motion includes usually two types: 铁石心肠 不可塑造