大学物理英文版.ppt

1、UNIVERSITY PHYSICS 1,大学物理（英文版） 多媒体课件,Introduction,Chapter 1 Kinematics,Chapter 2 Newtons Laws of Motion,Chapter 3 Work and Energy,Chapter 4 Momentum,Chapter 5 Rotation of a rigid body,Chapter 6 The Kinetic Theory of Gases,Chapter 7 Fundamentals of Thermodynamics,Volume 1,Introduction,2001.9.11 Catas

2、trophe（大灾难）,宇宙：约1250亿个星系，每个星系由数千亿个恒星组成。,银河系 太阳系：地球，星星 看得见的：你我他它 分子 原子 原子核 基本粒子,相对论 天体物理 经典物理:力学，热等 量子力学 核物理 量子场论,银河系,相对论 天体物理,量子天体 物理学,史蒂芬.霍金 时间简史, The Galaxy Sun: Earth,Planets The body we can see Molecules atoms nuclei elementary particles , The general reletivity astrophsics Newtons Mechanics Hea

3、t,Thermodynamics Electromagnetic Theory Quantum Mechanics Nuclear Physics Quantum Field Theory ,Theory,Our world and universe,宇宙半径：1026 m,地球1024 kg,银河系：1044 kg,我们的母亲： 地球,1969年7月16日 美国东部时间9时23分 阿波罗11号发射升空。,三天后 阿姆斯特朗 奥尔德林 柯林斯,Mars(火星）,机遇号,The surface of Mars(火星表面）,Our world and Universe,Universe,Eleme

4、ntary particles,The ancient physics,The classical physics,The modern physics,In the view of physics history:,主要讲授内容：,经典力学 相对论,热学,电磁学,波动光学,振动与波动,量子论简介,日常生活,Physics,Chemistry 化学,Biology 生物学,Computer 计算机科学,Mechanics 机械学,Medicine 医学,Physics: fundamentals and methods.,References(参考书）,张达宋 物理学基本教程 李行一等， 物理

5、学基本教程教学参考书 李行一等，物理学基本教程习题分析与解答 张三慧等， 大学物理学 Halliday et.al Fundamentals of Physics W. Sears et.al University Physics 史蒂芬.霍金，时间简史 盛正卯等，物理学与人类文明 B.K.里德雷，时间、空间和万物 .,Part One Mechanics 力学,Chapter 1 Kinematics （运动学）质点运动学,第一章 质点运动学(Kinematics),1-1 参考系 质点 Frame of reference particle,1-2 位置矢量 位移 Position vec

6、tor and displacement,13 速度 加速度 Velocity and acceleration,1-4 两类运动学问题 Two types of Problems,1-6 运动描述的相对性 Relative motion,1-5 圆周运动及其描述 Circular motion,1. 理解描述质点运动物理量的定义及其矢量性、相对性和瞬时性； 2. 掌握运动方程的物理意义，会用微积分方法求解运动学两类问题； 3. 掌握平面抛体运动和圆周运动的规律； 4. 理解运动描述的相对性，会用速度合成定理和加速度合成定理解题。,教 学基本 要 求,重要历史人物,伽利略Galileo Gal

7、ilei: 15641642意大利物理学家、数学家、天文学家，近代实验科学的创始人。,主要贡献： 发明了望远镜，维护、坚持和发展了哥白尼学说，发现木星的四个卫星； 摆的等时性、惯性定律、落体运动定律； 运动的合成原理和独立性原理，相对性原理； 方法：实验科学。,1-1 Frame of Reference Particle(质点）,1. Frame of Reference（参照系）,When we discuss the position and the velocity（速度） of an object ,we must answer the questions: “position wi

8、th respect to（相对于） what?” and “Velocity with respect to what?”,If we choose different objects as the reference frames to describe the motion of a given body,the indications(结果） will be different.,It is convenient to take the earths surface as our frame of reference in most cases in this course.( Wha

9、t cases?),Coordinate system（坐标系）: fixed on the frame, relative to which position, velocity, acceleration and orbit of the object can be specified quantitatively. Cartesian Coordinate system(直角坐标系）：,Quantitatively: 定量地,2. Particles（质点）,Particle(质点） is an ideal model, in some circumstances（情况、形势）. We

10、can treat a body as a particle, and concentrate on its translational motion(平动） and ignore（忽略） all the other motions.,点： 有质量 无大小 无体积,3. Time（时刻）and time interval(时间）,Time t is a given instant, and time interval(间隔）t is the difference of two given instants. We use the former to describe（描述） the state

11、 of the object, the latter to describe the process.（过程）,4.Units(单位）,International System of Units(SI: Systme International dUnits 法语） is used in China,kg:千克 kilogram,m:米 meter,s:秒 second,5. Scalar and vector（标量和矢量）:,Two types of physical quantities（量）:,Scalars: mass, length, speed, temperature.,Vect

12、ors: velocity, acceleration, momentum.,Vector A( black) : its magnitude(大小） and direction（方向） may be represented by a line OP directed from the initial point O to the terminal（终） point P and denoted（标记） by,Addition（加）: The two vectors A and B is added in following way: C=A+B B A,C,A,B,In Cartesian c

13、oordinate system（直角坐标系）:,are unit vectors along OX,OY,OZ,In two dimension（维）:,Obviously(显然）:,In one dimension In two dimension In three dimension,In our teaching, we will mainly deal with（涉及） two dimensional motions: motion in a plane.,Mechanical motions,（机械运动）,1-2 Position Vector and Displacement,1

14、. Position Vector,Position vector is a vector that extents from the origin of the coordinate system to the particles position as shown in Figure,Magnitude:,In the two dimension:,Its two components （分量）,Path equation(轨迹方程）,2. Displacement(位移):,Displacement is introduced to describe the change in posi

15、tion during a given time interval:,That is,Its magnitude（大小),The geometrical（几何） meaning of and the differences among them.,Note:,Solution:,1-3 Velocity（速度） and Acceleration（加速度）,Average（平均） velocity：,1.Velocity,which has a direction as same as that of,Average speed(速率）:,（Instantaneous 瞬时） velocity

16、at time t：,It is in the tangent(切线） of the path and points at the advance direction.,Direction:,Magnitude(大小）：,V-speed(瞬时）速率,时弧长等于弦长,In the coordinate system:,Magnitude of the velocity:,The angle formed between and +x direction is determined by,Example 1-2: A rabbit runs across a parking lot(近路） on

17、which a set of coordinate axes has, strangely enough, been draw. The coordinates of the rabbits position as function of time t are given by:,with t in seconds and x and y in meters. Find its velocity at t=0.50s.,Solution:,The rabbits velocity at t=0.50s is equal to(等于）,2.Acceleration(加速度),Average ac

18、celeration:,Instantaneous acceleration,In the coordinate system:,Its magnitude and direction:,指向曲线 凹的一方,Example 1.3: The of a Particle is,where and are constants. Find the velocity and acceleration.,Note: 微分，细心，再细心！ Carefully!,Solution:,Example 1. 4 已知质点运动方程为x=2t, y=192t2, 式中x, y以米计，t 以秒计，试求：（1）轨道方程

19、；（2）t=1s 时的速度和加速度。,（2）对运动方程求导，得到任意时刻的速度,对速度求导，得到任意时刻的加速度：,解：（1）运动方程联立，消去时间t得到轨道方程,（1）,(2),将时间t=1s代入速度和加速度分量式(1)、(2)中，求出时间t=1s对应的速度和加速度：,速度大小和与 x 轴夹角,加速度大小和方向：,与y轴正向相反,Example 1-5 离水平面高为h 的岸边，有人用绳以恒定速率V0拉船靠岸。试求：船靠岸的速度，加速度随船至岸边距离变化的关系式？,对时间求导得到速度和加速度：,由题意知：,解：在如图所示的坐标系中，船的位矢为：,因为：, 1-4 Two Types Probl

20、ems in Kinematics,（2） Given acceleration(or velocity) and initial condition, find the velocity and position vector by means of vector integration method 积分法.,In general, there are two kinds of problems to be solved:,(1) Given position vector, find the velocity and acce-leration by using derivation m

21、ethod 微分法. See the examples above.,解：整理和分离变量可得下面方程,做积分：,Example1.6: 某物体的运动规律为,式中k为常数，t=0，初速度为,求 .,得：,请同学们完成积分,Example1.7: A particle moves in a plane with an acce-leration ,where g is constant. When t=0,its velocity is at a initial point (0,0). Find its velocity at time t and path equation.,Using ,

22、we have,Using,and the initial condition(0,0), we have,Solution: Its velocity is,The position vector of the particle is,1-5 Circular Motion,1.The importance of Circular motion,(1) The movements of Sun, Earth, Planets , Electron, ., are related to circular motion;,(2) There are parts of instruments as

23、sociated with the circular motion: clock, car, .,(3) The knowledge on circular motion is the base to study the general curvilinear motion（曲线运动）.,You can accept(采用） the above method to study Circular Motion。,A particle is in circular motion if it travels around a circle or a circular arc（弧）.,Uniform

24、circular motion(匀速）: around a circle and at constant speed.,2.tangential（切向） ,Changes the direction of the velocity.,(2)Uniform circular motion (匀速) :,In this case， the magnitude of velocity is a constant， that is,which means that velocity changes only in direction. is usually called the centripetal acceleration（向心）.,Therefore, we have,3.General curvilinear motion:,(1-30),is the radius of curvature（曲率） at A and C is the center of curvature circle (曲