Space, as understood in Newtonian mechanics, is three-dimensional and Euclidean, with a fixed orientation. It is denoted E. If some point O in E is fixed and defined as an origin, the position of any point P in E is uniquely determined by its radius vector r = O P → → (the origin of this vector coincides with the point O and its end coincides with the point P). The three-dimensional linear vector space R is a set of all radius vectors. The space R is endowed with a scalar product ⟨, ⟩.