2019-2020学年度沪教版选修3-5第1章1.3动量守恒定律的案例分析(英文课件)(共13张PPT)

1.3动量守恒定律的案例分析 Collision in aspect of energy Sometimes when colliding objects contact, some part of kinetic energy may be or may not be transformed into other type of energy. i.e. heat or sound. Meanwhile the total energy is always conserved. Kinetic energy Kinetic energy Potential energy Heat or Sound Elastic collision The collision is elastic if the kinetic energy before collision is equal to the kinetic energy after collision. Kinetic energy Kinetic energy Potential energy And the total momentum, for an isolated system, is still conserved. Elastic collision Before collision: After collision: Example Ball A collides elastically on Ball B with speed u1. The masses of A and B is m1 and m2. Derive the outcome of the collision. A B u1 m1 m2 m1 m2 m1 m1 m2 m1=m2 m1>m2 m1<m2 Experiments Part I collide and separate verify m1=m2 cart1 cart2 Before collision After collision * Experiments Part II collide and stick together explore Question: momentum conserved?