Abstract
The problem of irreversibility in the classical mechanics is discussed.We have shown how this problem can be solved in the frame of the mechanics of the structural particles (SP).A brief physical justification for constructing of the structured particles (SP) mechanics is offers.The SP is equilibrium systems from sufficiently large number of potentially interacting material points.Unlike of the material point the SP has an inner energy.Therefore, the SP motion equation obtains from the principle of duality of symmetry.The SP dynamics is irreversible due to transform the SP motion energy into the internal energy in the external forces.Irreversibility of the SP dynamics allows introducing the concept of dynamical entropy and reveals its physical nature under the classical mechanics laws.The SP mechanic enables strictly describe dissipative processes of evolution of nonequilibrium systems.Some of problems from other sections of physics are discussed.