2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/62442We remove a small disc from the flat two-dimensional torus and consider a point-like particle that starts moving from the center of the disc with linear trajectory. We provide asymptotic estimates for the moments of the first exit time, with respect to the velocity, when the radius of the disc tends to zero.28 pages, 5 figuresNumber TheoryMathematical PhysicsDynamical Systems11B57; 82C40; 37D50; 58F25text