The rectilinear motion of a system of two interacting bodies when there is a dry friction force acting
on both of them is considered. It is assumed that the relative velocity of the bodies can vary practically
instantaneously, while the distance between them has upper and lower limits. The periodic motion of the
system as a whole is constructed, and the mean velocity of motion and the energy costs per unit of path
are determined. The optimum values of the parameters for which the highest mean velocity is reached
with the superimposed limitations are obtained.