2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/141445The notion of a rough two-dimensional (convex) body is introduced, and to each rough body there is assigned a measure on $\TTT^3$ describing billiard scattering on the body. The main result is characterization of the set of measures generated by rough bodies. This result can be used to solve various problems of least aerodynamical resistance.35 pagesDynamical SystemsOptimization and Control37N05, 49K30, 49Q10text