Its main objective is to understand physical phenomena, not chemical phenomena, not biological phenomena 其主要目标是理解物理现象，而不是化学现象，也不是生物现象
physicists try to understand how 物理学家试图理解如何
nature works in physical phenomenon and how nature behaves in such ways 自然在物理现象中运作，自然以这样的方式表现
an experimental science: physicists observe physical phenomena using experimental techniques 实验科学：物理学家使用实验技术观察物理现象
Develop theories, models, laws and principles to explain the physical phenomena 发展理论、模型、定律和原则以解释物理现象
What is Physics? 物理学是什么？
"Physics" comes from the Greek word phusika, meaning "natural things"-the study of philosophy and the natural world around them “物理学”源自希腊词 phusika，意为“自然事物”——对哲学和周围自然世界的研究
Physics is a natural science based on experiments, measurements and mathematical analysis with the purpose of finding patterns that relate the phenomena of nature. 物理学是一门基于实验、测量和数学分析的自然科学，旨在寻找与自然现象相关的规律。
The patterns are called physical theories. 这些模式被称为物理理论。
A very well established theory is called a physical law or principle. 一个非常成熟的理论被称为物理定律或原则。
For example, the description of motion 例如，运动的描述
You use a ruler to measure the position and a stop watch to measure the time 你用尺子测量位置，用秒表测量时间
Plot a position and time graph to describe the motion (Kinetics) 绘制位置与时间图以描述运动（动力学）
The motion can be explained using Newton's law (Dynamics) 该运动可以用牛顿定律（动力学）来解释
AP 1201 General Physics I AP 1201 普通物理 I
Physics: a brief history 物理学：简史
Ancient Greeks studied physics as a branch of philosophy 古希腊人将物理学作为哲学的一个分支进行研究
Socrates, Plato, Aristotle and Archimedes 苏格拉底、柏拉图、亚里士多德和阿基米德
Physics became a separate field by the century 物理学在 世纪成为一个独立的领域
Galileo, Kepler and Newton helped pioneer the use of mathematics as a fundamental tool in physics 伽利略、开普勒和牛顿帮助开创了将数学作为物理学基本工具的使用
In the 1800s, the laws of electricity, magnetism and electromagnetic waves were developed: Faraday and Maxwell 在 19 世纪，电、磁和电磁波的定律被发展起来：法拉第和麦克斯韦
The laws of heat and work, and molecular origin: Kelvin, Boltzmann 热与功的定律及其分子起源：开尔文，玻尔兹曼
Modern Physics started by late to early century 现代物理学始于 世纪末到 世纪初
discovery of X-rays (Röntgen 1895), radioactivity (Becquerel 1896), the quantum hypothesis (Planck 1900), relativity (Einstein 1905) and atomic theory (Bohr 1913) X 射线的发现（伦琴 1895），放射性（贝克勒尔 1896），量子假说（普朗克 1900），相对论（爱因斯坦 1905）和原子理论（玻尔 1913）
Development of quantum mechanics revolutionized physics and allowed a better understanding of matters in the atomic, molecular, nuclear, and sub-nuclear scale 量子力学的发展彻底改变了物理学，使我们更好地理解原子、分子、核及亚核尺度的事物
Physics is the foundation of modern technologies 物理学是现代技术的基础
Engineers need to know physics 工程师需要了解物理学
Civil engineer: force, equilibrium in a bridge 土木工程师：桥梁中的力与平衡
Mechanical engineer: motion in a car engine 机械工程师：汽车发动机中的运动
Biomedical: force in artificial joint 生物医学：人工关节中的力
Electrical & electronics: current in devices, motion of a motor 电气与电子：设备中的电流，电动机的运动
Chemical engineer: entropy, reaction dynamics 化学工程师：熵，反应动力学
An Excellent Beach Book about Physics 一本关于物理的优秀海滩书籍
A CGMPLETE EDUCATIGN-WITHEUT THE TUITIGN: 完整教育——无需学费：
I T 我 T
FRIM ARISTITLE TI EINSTEIN, AND BEYIND 弗里姆·阿里斯提尔·爱因斯坦，以及超越
TロNY.RワTHMAN, PH.D. T 罗 NY.R 瓦斯曼，博士。
QVERCIME INERTIA AND LEARN HIW THIS QVERCIME 惯性并学习如何做到这一点
BRAVE NEW WIRLD WIRKS! 勇敢的新世界运作！
For all of you who break out in a sweat at the thought of thermodynamics, or freeze up at the mention of quantum mechanics, like a bolt from the blue, Instant Physics will zap you through the fascinating history of our most basic, yet baffling, science. 对于所有一想到热力学就出汗，或提到量子力学就感到紧张的人来说，《瞬间物理》将带你迅速穿越我们最基本却又令人困惑的科学的迷人历史。
From the thousand-year search for proof of the existence of the ever-elusive atom to the varied and heated arguments behind the big bang theory, Instant Physics answers all the heavy questions with a light touch. Dr. Tony Rothman explains in clear prose the inner workings of Newton's apple and Maxwell's electromagnetic waves and simultaneously offers wry observations about the state of physics in the world today. 从千年寻找永 elusive 原子的存在证明，到关于大爆炸理论的各种激烈争论，《瞬间物理》以轻松的方式回答所有重大问题。托尼·罗斯曼博士用清晰的语言解释了牛顿的苹果和麦克斯韦的电磁波的内在运作，同时对当今物理学的现状提出了尖锐的观察。
With Instant Physics you'll learn: 通过即时物理，您将学习：
How the Greek philosophers used the sledgehammer of mathematics to break apart the mysteries of the physical universe. 希腊哲学家如何利用数学的巨锤来揭开物理宇宙的奥秘。
Why gravity is a "romantic" force. 为什么引力是一种“浪漫”的力量。
Enough of Einstein's theories of relativity to discuss knowingly the derivation of . 足够的爱因斯坦相对论理论，以便能够知晓地讨论 的推导。
How to tell the difference between a gluon, a meson, and a quark, even if you can't see them. 如何区分胶子、介子和夸克，即使你看不见它们。
Instant Physics is crammed with special features, including chapter summaries, who's who lists, biographical and historical tidbits, and a host of illustrations, photos, equations, diagrams, and drawings. 《瞬间物理》充满了特别的内容，包括章节摘要、人物介绍、传记和历史小知识，以及大量插图、照片、方程式、图表和图画。
Tony Rothman, Ph.D., is an associate at Harvard College Observatory and teaches physics and astronomy at Bennington College. He is the author of A Physicist on Madison Avenue and Science à la Mode. 托尼·罗斯曼，博士，是哈佛大学天文台的副研究员，并在本宁顿学院教授物理和天文学。他是《麦迪逊大道上的物理学家》和《时尚科学》的作者。
INSTANT l HVEICE 即时 l HVEICE
PRICE 价格
ISBN 0-449-90693-3
NSTANT PHYSICS ||II|||||||||||||||||| |||||||| 51195 瞬时物理学 ||II|||||||||||||||||| |||||||| 51195
Physics as it was developing by a Nobel Laureate 诺贝尔奖得主所发展的物理学
AP 1201 General Physics I AP 1201 普通物理 I
Topics for Chapter 1 第一章主题
Units, physical quantities 单位，物理量
Dimensional analysis 维度分析
Vectors and Scalars 向量和标量
add vectors graphically 图形化地添加向量
vector components 向量分量
unit vectors and components 单位向量和分量
multiplying vectors 向量相乘
A little calculus: 一点微积分：
some basic derivatives (differentiation) of functions 一些函数的基本导数（微分）
Basic concept of integration 积分的基本概念
Standards and Units* 标准和单位*
Length, time, and mass are three fundamental quantities of physics. 长度、时间和质量是物理学的三个基本量。
The International System (SI for Système International) is the most widely used system of units. 国际单位制（SI，法语为 Système International）是使用最广泛的单位制。
In SI units, length is measured in meters, time in seconds, and mass in kilograms. 在国际单位制中，长度以米为单位，时间以秒为单位，质量以千克为单位。
Units of measurement* 计量单位*
Dimension 维度
SI (mks) Unit 国际单位制（米千克秒）单位
Definition 定义
TABLE 1.4 表 1.4
Length 长度
meters (m) 米 (m)
光在 秒内行驶的距离
Distance traveled by
light in
second
一些用于“公制”（SI 和 cgs）单位的 10 的幂的前缀
Some Prefixes for Powers of
10 Used with "Metric" (SI
and cgs) Units
Power 权力
Prefix 前缀
Abbreviation 缩写
atto- 阿托-
a
Mass 弥撒
kilogram (kg) 千克 (kg)
Mass of a specific 特定的质量
pico- 皮克
kilogram (kg) 千克 (kg)
platinum-iridium alloy 铂铱合金
纳米- 微米-
nano-
micro-
cylinder kept by Intl. 国际保留的气缸
milli- 毫-
m
Bureau of Weights and 计量局
centi- 厘-
c
Measures at Sèvres, 塞夫尔的措施，
deci- 分之一
d
France 法国
deka- 德卡-
Time 时间
seconds (s) 秒 (s)
铯-133 原子进行 9,192,631,700 次完整振荡所需的时间
Time needed for a
cesium-133 atom to
perform 9,192,631,700
complete oscillations
mega- 兆-
M
giga- 千兆-
G
tera- 特拉-
T
皮塔- 艾克萨-
peta-
exa-
P
exa-
Cole E 科尔·E
Dimensional Analysis* 维度分析*
An equation must be dimensionally consistent. Terms to be added or equated must always have the same units. (Be sure you're adding "apples to apples.") 一个方程必须在维度上保持一致。要相加或相等的项必须始终具有相同的单位。（确保你是在“加苹果对苹果。”）
Always carry units through calculations. 始终在计算中保留单位。
Convert to standard units as necessary. 根据需要转换为标准单位。
Dimensions & units can be treated algebraically. 维度和单位可以用代数方式处理。
Variable from Eq. 从方程中得出的变量。
x
m
t
dimension 维度
L
M
T
Dimensional Analysis* 维度分析*
Checking equations with dimensional analysis: 通过维度分析检查方程：
Each term must have same dimension 每个项必须具有相同的维度
Two variables cannot be added if dimensions are different 两个变量的维度不同则无法相加
Multiplying variables is always fine 乘法变量总是可以的
Numbers (e.g. 1/2 or ) are dimensionless 数字（例如 1/2 或 ）是无量纲的
Example 1.1* 示例 1.1*
Check the equation for dimensional consistency: 检查方程的维度一致性：
Here, is a mass, g is an acceleration, v and are velocities, is a length 这里， 是一个质量，g 是加速度，v 和 是速度， 是长度
Example 1.2* 示例 1.2*
Consider the equation: 考虑方程：
Where and are masses, is a radius and is a velocity. What are the dimensions of ? 其中 和 是质量， 是半径， 是速度。 的维度是什么？
Units vs. Dimensions* 单位与维度*
Dimensions: L, T, M, L/T ... 尺寸：L，T，M，L/T ...
Units: m, mm, cm, kg, g, mg, s, hr, years ... 单位：米，毫米，厘米，千克，克，毫克，秒，小时，年……
When an equation is all algebraic: check dimensions 当一个方程是全代数时：检查维度
When numbers are inserted: check units 当插入数字时：检查单位
Units obey same rules as dimensions: Never add terms with different units 单位遵循与维度相同的规则：绝不要将不同单位的项相加
Angles are dimensionless but have different units (degrees or radians) 角度是无量纲的，但有不同的单位（度或弧度）
In physics or never occur unless Y is dimensionless 在物理学中， 或 只有在 Y 是无量纲时才会发生
Two kinds of quantities 两种数量
In physics, we must handle quantities, such as your weight, your height. 在物理学中，我们必须处理数量，例如你的体重和身高。
Quantities can be obtained from experiments. 数量可以通过实验获得。
Quantities are usually represented by numbers 数量通常用数字表示
There are two kinds of quantities: scalar and vector 有两种量：标量和向量
Vectors and scalars 向量和标量
A scalar is a quantity represented by a single number, such as your weight or height 标量是由一个单一数字表示的量，例如你的体重或身高
A vector is a quantity having both a magnitude and a direction. 向量是具有大小和方向的量。
a vector is usually represented by a letter with an arrow over it: or or simply . 一个向量通常用一个字母上面加一个箭头来表示： 或 或简单地 。
Magnitude of is represented by or . 的大小由 或 表示。
A typical example of vector: position of Kowloon Tong station relative to the Central station. 一个典型的向量例子：九龙塘站相对于中环站的位置。
Vector (relative position) 向量（相对位置）
The relative position of Kowloon Tong with respect to Central is a vector. 九龙塘相对于中环的位置是一个向量。
It tells you how to get to Kowloon Tong from central: 它告诉你如何从市中心到达九龙塘：
Walk a distance along a certain direction 沿着某个方向走一段距离
If the direction is changed, you go to the wrong place (red arrow) if you go for the same 如果方向改变，你会去错误的地方（红箭头），如果你走的是相同的方向
distance 距离
Other vector physical quantities 其他矢量物理量
Apart from displacement, the following physical quantities are also vectors: 除了位移，以下物理量也是向量：
Velocity, momentum (come from position) 速度，动量（来自位置）
Angular velocity, angular momentum (come from position) 角速度，角动量（来自位置）
Acceleration, force 加速度，力
electric field, magnetic field 电场，磁场
They are usually related to motion and force 它们通常与运动和力有关
Vector representation 向量表示
Graphically a vector is represented by a line with an arrowhead at its tip. 图形上，向量用一条带箭头的线表示。
The length of the line represents the vector's magnitude. 线的长度表示向量的大小。
The arrow direction represents the vector's direction. 箭头方向表示向量的方向。
The red vector is different from the black one although their magnitudes are the same 红色向量与黑色向量不同，尽管它们的大小相同
A vector can be written in terms of the coordinates: 一个向量 可以用 坐标表示：
Magnitude can be represented by a number in the figure 大小可以用图中的数字 表示
Direction can represented by the angle made with a fixed direction, angle made with the x-axis, so that 方向可以通过与固定方向形成的角度来表示，角度 与 x 轴形成，因此
Adding two vectors graphically 图形化地添加两个向量
Two or more vectors may be added graphically 两个或多个向量可以通过图形方式相加
Vector addition is commutative, i.e. does not depend on the order 向量加法是交换的，即不依赖于顺序。
(a)
(b)
(c)
Vector Addition: head to tail method 向量加法：头尾法
Adding 2 vectors by placing them head to tail, the resultant vector can be drawn from the origin to the end 将两个向量首尾相接相加，结果向量可以从原点绘制到末端
It is independent on the order, adding in different order gives the same result 它与顺序无关，以不同的顺序添加会得到相同的结果
Same result can be achieved by constructing a parallelogram with the vector pointing to the vertex between vectors and 通过构造一个平行四边形，使用指向向量 和 之间顶点的向量，可以实现相同的结果
Several vectors can be added using the head to tail method 可以使用头尾法将多个向量相加
Vector Subtraction 向量减法
Vector subtraction is similar to vector addition 向量减法类似于向量加法
Multiplying a vector by a scalar 将向量乘以标量
If is a scalar, the product has magnitude . 如果 是一个标量，则乘积 的大小为 。
Multiplying a vector by a positive scalar changes the magnitude of the 将一个向量乘以一个正标量会改变其大小
vector but not he direction 向量但不是方向
Multiplying a vector by a negative scalar reverses the direction and changes the magnitude of the vector 将一个向量乘以一个负标量会反转向量的方向并改变其大小
Components of a vector 向量的组成部分
Adding vectors graphically may not be accurate and is not convenient 图形化地相加向量可能不准确且不方便
Vector components provide a general method for adding vectors. 向量分量提供了一种添加向量的通用方法。
Any vector can be represented by an -component and a component . and directions are usually perpendicular. 任何向量都可以由一个 -分量 和一个 分量 表示。 和 方向通常是垂直的。
Use trigonometry to find the components of a vector: and , where is measured from the -axis toward the -axis. 使用三角学找到一个向量的分量： 和 ，其中 是从 轴测量到 轴的。
Magnitude of the vector : 向量 的大小：
Positive and negative components 正负组件
The components of a vector can be positive or negative numbers, as shown in the figure. 向量的分量可以是正数或负数，如图所示。
If the component is pointing to the negative direction, then the component is a negative number 如果分量指向负方向，那么该分量是一个负数
For both component vectors point in the +ve directions 对于 ，两个分量向量都指向正方向
pointing in the direction 指向 方向 pointing in the +y direction pointing in the direction 指向 +y 方向 指向 方向 pointing in the -y direction 指向 -y 方向
Example 示例
Given: 给定：
Given: 给定：
A vector in 3-D 三维中的向量
Similar to the 2-D case, in 3-D a vector can be represented by an -component , a -component and a component 类似于二维情况，在三维中，一个向量 可以由一个 -维 、一个 -维 和一个 维 表示
Unit vectors: units for Cartesian coordinates 单位向量：笛卡尔坐标的单位
A vector can be expressed by its components and in 3 dimensions along the and z axes 一个向量 可以通过其在 和 方向上的分量在三维空间中表示，沿着 和 z 轴
Unit vectors are dimensionless vectors along the axes with length=1, i.e. just indicating the direction 单位向量是沿着 轴的无量纲向量，长度为 1，即仅表示方向。
For two dimension, we need two unit vectors. For three dimension, we need three unit vectors. 对于二维，我们需要两个单位向量。对于三维，我们需要三个单位向量。
The unit vector points in the direction, points in the -direction, and points in the -direction 单位向量 指向 方向， 指向 方向， 指向 方向
All vectors can be expressed in terms of unit vectors 所有向量都可以用单位向量表示
