Abstract: Impact stress analysis is an essential part of the energy method in mechanics of materials. Taking the classic buffering problem of an elastically supported beam struck by a falling weight as an example, dynamic equations are established based on the theory of impact dynamics. Two models are of interest: the elastic contact-separation model, and the non-separation model in which the striking body remains in contact with the beam after impact. Through numerical examples, the maximum impact loads predicted by impact dynamics and the energy method in mechanics of materials are compared, and the inertia effects of the beam mass and the applicability of mechanics of materials in analyzing elastic buffering problems are discussed. This work may help students gain a deeper understanding of impact and buffering problems and their applications in engineering.