Chapter 3 Work and energy 第三章功和能
第三章 功 和 能 Chapter 3 Work and Energy
§3-1Work(功) §3-2 Kinetic Energy(动能) and the law of Kinetic Energy(动能定理) §3-3 Conservative force(保守力)& Potential Energy of Weight Elastic potential energy (弹性势能) Universal gravitational Potential Energy §3-4 Conservation of Mechanical Energy(机械能) 83-5 The Conservation of Energy
§3-1 Work（功） §3-2 Kinetic Energy（动能）and The Law of Kinetic Energy（动能定理） §3-3 Conservative Force（保守力） & Potential Energy of Weight Elastic Potential Energy （弹性势能） Universal Gravitational Potential Energy §3-4 Conservation of Mechanical Energy（机械能） §3-5 The Conservation of Energy
教学基本要求 1掌握变力作功的计算和动能定理的应用 2.掌握保守力作功作功特点及与相关势能 的关系; 3.明确功与能(动能、势能)关系与区别 4.掌握机械能守恒定律的物理意义及应用 条件
1.掌握变力作功的计算和动能定理的应用； 2. 掌握保守力作功作功特点及与相关势能 的关系； 3. 明确功与能（动能、势能）关系与区别； 4. 掌握机械能守恒定律的物理意义及应用 条件. 教学基本要求
Energy is an important concept in Physics, which was introduced by Thomas Young in 1807 能量守恒 Grag and Korea Pr) The following physicists who made greater contributions to the discovery of the conservation of Energy(能量守恒):
Energy is an important concept in Physics, which was introduced by Thomas Young in 1807. The following physicists who made greater contributions to the discovery of the Conservation of Energy（能量守恒）： 能量守恒 (Iraq and Korea(D.P.R)
迈尔( Robert mayer,1814-1878),德国物理学 家,医生,第一个提出能量守恒的科学家; 亥姆霍兹( Hermann Von Helmhotz, 1821-1894),德国物理学家,生理学家,系统地论 述了能量守恒定理; 焦耳(J,P. Joule, 1818-1889),英国物理学家, 发现能量守恒及转换定理的 主要代表
焦 耳 （ J. P. Joule, 1818~1889),英国物理学家， 发现能量守恒及转换定理的 主要代表。 迈尔（Robert Mayer, 1814~1878),德国物理学 家，医生，第一个提出能量守恒的科学家； 亥姆霍兹（Hermann Von Helmhotz, 1821~1894)，德国物理学家，生理学家，系统地论 述了能量守恒定理；
Energy: The conservation of energy must be satisfied(p 足) in all the processes(过程) in the nature.The different types of physical 'motions'are transformed(+t 化) through the important link of energy(纽带)
Energy：The conservation of energy must be satisfied（满 足） in all the processes（过程） in the nature. The different types of physical ‘motions’ are transformed（转 化） through the important link of Energy(纽带）
F16 机械运动 化学能量 气体热运动
化学能量 气体热运动 机械运动 F16
§3-1Work(功) 1. Work done by a constant force The work done by F is iven by g 0 0 W=(F 0)S(3-1) orl W=F.S(3-2) The si unit of w is joule 1Joule=1J=IN m=1kg.m2/s2
§3-1 Work（功） 1. Work done by a constant force F F s The work done by is given by F W F S = (3-2) W = (F cos )S (3-1) (or) The SI unit of W is Joule : 1Joule =1J = 1N·m = 1kg·m2 /s2
箭箭击中100环 学习要用功 方法要对路
箭箭击中100环 学习要用功 方法要对路
2. Work done by a variable force(变力的功) F is a variable force(3])acting on a particle moving along a curvilinear(曲线) path. Let us find the work done(作功) by it as follows:
2. Work done by a variable force（变力的功） is a variable force (变力) acting on a particle moving along a curvilinear（曲线） path. Let us find the work done （作功）by it as follows ： F i r Fi i