ИСТИНА

The motion of two interacting bodies along a straight line on a horizontal plane is studied. Coulomb’s dry friction is assumed to act between the bodies and the supporting plane. The distance between the bodies and their velocities change periodically in time. Necessary and sufficient conditions for the existence of a motion in which neither of the bodies moves in the direction opposite to that of the displacement of the system for the period are found. Such motions are called non-reverse motions. The advantage of the non-reverse motions is that they provide a minimum for the energy consumption on friction per unit path