Chapter 2&3 Kinematics Chapter 2 &3 Motion in one Dimension. Two and Three Dimensions 1. Reference frames and displacement 2. Velocity 3. Acceleration 4. Circular motion
Chapter 2&3 Kinematics Chapter 2 & 3 Motion in One Dimension, Two and Three Dimensions 1. Reference Frames and Displacement 2. Velocity 3. Acceleration 4. Circular Motion
New words Reference frames 参考系 Position 位置 Displacement 位移 S peed 速率 Velocity 速度 Acceleration 加速度 Circular motion 圆周运动 Relative motion 相对运动 Translational motion 平动 Particle 质点
New Words Reference Frames 参考系 Position 位置 Displacement 位移 Speed 速率 Velocity 速度 Acceleration 加速度 Circular Motion 圆周运动 Relative Motion 相对运动 Translational motion 平动 Particle 质点
Chapter 2&3 Kinematics Mechanics(力学): The Science of motion and its causes Mechanics is customarily divided into two parts Kinematics(运动学)→> description of motion.( Chapter2 3, P16-P76) Dynamics(动力学)→ causes of motion (Chapter4-11, P77-P296)
Chapter 2&3 Kinematics Mechanics（力学）: The Science of motion and its causes. Kinematics（运动学）→ description of motion. (Chapter2 & 3, P16 - P76) Dynamics（动力学）→ causes of motion. (Chapter4-11, P77 – P296) Mechanics is customarily divided into two parts:
Chapter 2&3 Kinematics 2-1&3-6 Reference frames(参考系) and Displacement(位移)P17-18 The world, and everything in it, moves. Even seemingly stationary things, such as a house moves with the earth. the earth's orbit around the sun. the suns orbit around the center of the milky Way galaxy, and that galaxy's migration relative to other galaxies 绝对静止的物体是没有的运动的绝对性
Chapter 2&3 Kinematics 2-1&3-6 Reference Frames （参考系） and Displacement（位移）P17-18 The world, and everything in it, moves. Even seemingly stationary things, such as a house moves with the Earth, the Earth’s orbit around the Sun, the Sun’s orbit around the center of the Milky Way galaxy, and that galaxy’s migration relative to other galaxies. 绝对静止的物体是没有的—— 运动的绝对性
Chapter 2&3 Kinematics 1 Reference frame参考系 To describe the position of an object, the other object referred to( Reference frame参照系) should be chosen. It is arbitrary 为描述物体的运动而选择的标准物叫做参考系. 选取的参考系不同,对物体运动情况的描述不 同,这就是运动描述的相对性
Chapter 2&3 Kinematics To describe the position of an object, the other object referred to (Reference Frame 参照系） should be chosen. It is arbitrary. 为描述物体的运动而选择的标准物叫做参考系. 选取的参考系不同，对物体运动情况的描述不 同，这就是运动描述的相对性. 1 Reference Frame 参考系
Chapter 2&3 Kinematics 2 Coordinate system(坐标系) z(t (t) Origin O(坐标原点) rty X and y axes(xy轴) y(t) The x and y axes are x(t o always perpendicular to each other Rectangular-直角坐标系(x,y,z) Natura-自然坐标系(s)
Chapter 2&3 Kinematics 2 Coordinate system (坐标系) x ^ y ^ z ^ x · z y z( t ) y( t ) x( t ) r( t ) P( t ) 0 Rectangular-直角坐标系（ x , y , z ） Natural-自然坐标系 ( s ) Origin O (坐标原点) x and y axes (x,y 轴) The x and y axes are always perpendicular to each other
Chapter 2&3 Kinematics 3 Particle(质点):P16 个具有质量而没有大小和形状的理想物体。 突出了质量和位置 Every portion of object moves in the same direction and the same rate It has only translational motion(平移运动)
Chapter 2&3 Kinematics 一个具有质量而没有大小和形状的理想物体。 突出了质量和位置。 Every portion of object moves in the same direction and the same rate. 3 Particle (质点): P16 It has only translational motion (平移运动)
Chapter 2&3 Kinematics 4 Position vector(位置矢量P52) The location of a particle relative to the origin (原点) of a coordinate system 确定质点P某一时刻在 坐标系里的位置的物理量称 位置矢量,简称位矢F P For a Cartesian system: r=xi +vi+zk X 式中1、k分别为x、y、z 方向的单位矢量
Chapter 2&3 Kinematics The location of a particle relative to the origin (原点） of a coordinate system. r For a Cartesian system: * P x y z x z y o j i k 确定质点P某一时刻在 坐标系里的位置的物理量称 位置矢量, 简称位矢 r . r xi yj zk = + + 式中 、 、 分别为x、y、z 方向的单位矢量. i j k 4 Position Vector(位置矢量P52）
Chapter 2&3 Kinematics 位矢P的值为 2 xty+z 5 Motion function(运动方程) P)F(t)=x(1)+y(t)+z(1)k x=x() 0)分量式{y=y() z=Zt 从中消去参数t得轨迹方程 f(x,y,-)=0
Chapter 2&3 Kinematics P (x,y,z,t ) i k j x y z (t0 ) r(t) (t ) z x y 5 Motion Function (运动方程)： 2 2 2 位矢 r 的值为 r r x y z = = + + r t x t i y t j z t k ( ) = ( ) + ( ) + ( ) x = x(t) y = y(t) z = z(t) 分量式 从中消去参数 得轨迹方程 f (x, y,z) = 0 t
Chapter 2&23 Kinematics 6 Displacement(位移矢量p17,52) a particle is char△ rg in its position(描述质点空间 位置变化的矢量 △入B yB+才 △B VA B x O Bx 经过时间间隔△t后,质点位置矢量发生变化,由 始点A指向终点B的有向线段AB称为点A到B的 位移矢量ΔF.位移矢量也简称位移
Chapter 2&3 Kinematics 6 Displacement (位移矢量p17,52) x y o B B r A r A r A r B B r A r x y o B x A x B A x − x B y A y B A y − y 经过时间间隔 后, 质点位置矢量发生变化, 由 始点 A 指向终点 B 的有向线段 AB 称为点 A 到 B 的 位移矢量 . 位移矢量也简称位移. t r A particle is changing in its position(描述质点空间 位置变化的矢量). r Δ