COLLISION: A BLIND SPOT IN “PARTICLE AND RIGID-BODY DYNAMICS”

Collision is a kind of mechanical phenomena which widely exist in nature, people’s live, sports and engineering. After a brief review of historical development, the article summarizes the fundamental laws of collinear collision between two particles/bodies, and points out that the particle dynamics only provides us the law of momentum conservation and the momentum-impulse theorem, with no information on the magnitude and pulse shape of colliding force, or on energy loss during collision. The mechanical models of collision based on linear elasticity, contact mechanics and elastoplastic theory are respectively illustrated, indicating that the coefficient of restitution (COR) is not a material constant. Finally, the article calls for making up the knowledge of collision dynamics in the teaching reform of basic mechanics, so as to help students to establish correct concepts.