The dynamics of a brake shoe and “impact generated by friction”

The interaction between a wheel and a brake shoe is discussed. It is noted that there is a critical set of parameters for which the friction force can take an arbitrary value. The phenomenon of “impact generated by friction” occurs in the system in the subcritical domain of the parameters. Versions of the post-impact behaviour of the bodies are described; one of them, the stopping of the wheel and the recoil of the brake shoe, corresponds to the process scenario described by Bolotov. It is also shown that it is possible for the wheel to rotate in the opposite direction.