In this paper an idea of studying rheonomic problems for system of $N$ particles as the "relative motion" is developed. Meaning of the "relative motion" should be assumed as the generalization of the classical relative motion. While the last one assumes transferred motion to be the rigid motion only (translation and rotation) the first one implies deformation as well. Deformation can be pure deformation and the deformation that changes the shape (the angles) of the surface. In that way acceleration of a representative particle consisted of three components: relative, transferred, and so cold "added" acceleration. It was shown that Coriolis acceleration is only the special case of "added" acceleration, i.e. in a case when transferred motion is rigid rotation only.