Chapter 9 Center of Mass and Linear Momentum 第九章 質心與線動量

Chapter 9 Center of Mass and Linear Momentum 9-1 What is Physics? 9-2 The Center of Mass 9-3 Newton’s Second Law for a System of Particles 9-4 Linear Momentum 9-5 The Linear Momentum of a System of Particles 9-6 Collision and Impulse 9-7 Conservation of Linear Momentum 9-8 Momentum and Kinetic Energy in Collisions 9-9 Inelastic Collisions in One Dimension 9-10 Elastic Collisions in One Dimension 9-11 Collisions in Two Dimensions 9-12 Systems with Varying Mass: A Rocket

9-1 What is Physics? mechanical engineer 機械工程師 ballerina 芭蕾女舞者 leap 跳 jump 跳 hop 跳 parabola 拋物線 parabolic 拋物線的 center of mass 質心 long jump (board jump) 跳遠 hop, step, and jump 三級跳遠

Center of Mass 質心

9-2 The Center of Mass The center of mass of a system of particles is the point that moves as through (1) all of the system’s mass were concentrated there and (2) all external forces were applied there. solid body 實心體

Sample Problem

9-3 Newton’s Second Law for a System of Particles External force Internal force System

Sample Problem

9-4 Linear Momentum 線動量

9-5 The Linear Momentum of a System of Particles

9-6 Collision and Impulse 碰撞與衝量

Sample Problem

9-7 Conservation of Linear Momentum

Sample Problem

9-8 Momentum and Kinetic Energy in Collisions Elastic collision 彈性碰撞 – 動能守恆 Inelastic collision 非彈性碰撞 – 動能不守恆 Completely inelastic collision 完全非彈性碰撞 – 動能不守恆

9-9 Inelastic Collisions in One Dimension One-Dimensional Inelastic Collisions One-Dimensional Completely Inelastic Collisions

One-Dimensional Inelastic Collisions

One-Dimensional Completely Inelastic Collisions

Sample Problem

9-10 Elastic Collisions in One Dimension

Sample Problem

9-11 Collisions in Two Dimensions glancing collision 掠射碰撞

9-12 Systems with Varying Mass: A Rocket