  Dynamics of the structured particles consisting of potentially interacting
material points is considered in the framework of classical mechanics.
Equations of interaction and motion of structured particles have been derived.
The expression for friction force has been obtained. It has been shown that
irreversibility of dynamics of structured particles is caused by increase of
their internal energy due to the energy of motion. It has been shown also that
the dynamics of the structured particles is determined by two types of
symmetry: the symmetry of the space and the internal symmetry of the structured
particles. Possibility of theoretical substantiation of the laws of
thermodynamics has been considered.
