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PEARSON EDEXGEL INTERNATIONAL AS / A LEVEL
皮尔森爱德思格尔国际A/A级考试

PHYSICS STUDENT BOOK 1 物理学生用书 1

MILES HUDSON 米尔斯-胡森

PDF COMPILED BY SAAD pdf 由 saad 编制

PEARSON EDEXCEL INTERNATIONAL AS/A LEVEL PHYSICS
皮尔森爱德思国际A/A级物理

Student Book 1 学生用书 1
Miles Hudson 迈尔斯-哈德森
Published by Pearson Education Limited, 80 Strand, London, WC2R ORL.
培生教育有限公司出版,80 Strand, London, WC2R ORL。

www.pearsonglobalschools.com
Copies of official specifications for all Pearson Edexcel qualifications may be found on the website: https://qualifications.pearson.com
所有 Pearson Edexcel 资格证书的官方规格副本均可在网站上找到:https://qualifications.pearson.com
Text © Pearson Education Limited 2018
文本 © 培生教育有限公司 2018

Designed by Tech-Set Ltd, Gateshead, UK
由英国盖茨黑德 Tech-Set 有限公司设计

Edited by Kate Blackham and Jane Read
编辑:凯特-布莱克姆和简-雷德

Typeset by Tech-Set Ltd, Gateshead, UK
由英国盖茨黑德 Tech-Set 有限公司排版

Original illustrations © Pearson Education Limited 2018
原创插图 © 培生教育有限公司 2018

Cover design by Pearson Education Limited 2018
封面设计:培生教育有限公司 2018

Picture research by Aptara, Inc
Aptara 公司的图片研究

Cover photo © RUSSELL CROMAN/SCIENCE PHOTO LIBRARY
封面照片 © RUSSELL CROMAN/SCIENCE PHOTO LIBRARY

Inside front cover photo: Dmitry Lobanov
封面内页照片:德米特里-洛巴诺夫

The right of Miles Hudson to be identified as author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
迈尔斯-赫德森已根据 1988 年《版权、外观设计和专利法》申明了其作为该作品作者的权利。
First published 2018 2018 年首次出版
21201918
10987654321
British Library Cataloguing in Publication Data
大英图书馆出版数据编目

A catalogue record for this book is available from the British Library
大英图书馆可提供此书的目录记录

ISBN 9781292244877
All rights reserved. No part of this publication may be reproduced in any form or by any means (including photocopying or storing it in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright owner, except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency, Barnard’s Inn, 86 Fetter Lane, London EC4A 1EN (www.cla.co.uk). Applications for the copyright owner’s written permission should be addressed to the publisher.
保留所有权利。未经版权所有者的书面许可,不得以任何形式或通过任何方式复制本出版物的任何部分(包括影印或通过电子手段将其存储在任何介质中,无论是否短暂复制或附带于本出版物的其他用途),除非符合《1988 年版权、设计和专利法》的规定,或根据版权许可机构(Copyright Licensing Agency, Barnard's Inn, 86 Fetter Lane, London EC4A 1EN)颁发的许可条款(www.cla.co.uk)。版权所有者的书面许可申请应向出版商提出。
Printed by Neografia in Slovakia
由斯洛伐克 Neografia 印刷

Endorsement statement 认可声明

In order to ensure that this resource offers high-quality support for the associated Pearson qualification, it has been through a review process by the awarding body. This process confirmed that this resource fully covers the teaching and learning content of the specification at which it is aimed. It also confirms that it demonstrates an appropriate balance between the development of subject skills, knowledge and understanding, in addition to preparation for assessment.
为确保本资料能为相关培生资格证书提供高质量的支持,本资料已通过授证机构的审查程序。审查结果表明,本教材完全涵盖了其所针对的规范的教学内容。它还证实,除了为评估做准备外,它还在学科技能、知识和理解能力的发展之间实现了适当的平衡。
Endorsement does not cover any guidance on assessment activities or processes (e.g. practice questions or advice on how to answer assessment questions) included in the resource, nor does it prescribe any particular approach to the teaching or delivery of a related course.
认可不包括资源中包含的任何有关评估活动或过程的指导(如练习题或有关如何回答评估问题的建议),也不对相关课程的教学或实施规定任何特定的方法。
While the publishers have made every attempt to ensure that advice on the qualification and its assessment is accurate, the official specification and associated assessment guidance materials are the only authoritative source of information and should always be referred to for definitive guidance.
尽管出版商已尽力确保有关资格及其评估的建议准确无误,但官方规范和相关评估指导材料是唯一权威的信息来源,应始终参考以获得明确的指导。
Pearson examiners have not contributed to any sections in this resource relevant to examination papers for which they have responsibility.
培生主考官没有参与本资料中与其负责的试卷相关的任何部分。
Examiners will not use endorsed resources as a source of material for any assessment set by Pearson. Endorsement of a resource does not mean that the resource is required to achieve this Pearson qualification, nor does it mean that it is the only suitable material available to support the qualification, and any resource lists produced by the awarding body shall include this and other appropriate resources.
考官不得将认可的资源作为培生设置的任何评估的材料来源。对某一资源的认可并不意味着该资源是获得该培生资格证书的必备资源,也不意味着该资源是支持该资格证书的唯一合适材料。

Acknowledgements 致谢

Logos 徽标

Logo on page 168 from LIFEPAK® 1000 DEFIBRILLATOR brochure, http://www. physio-control.com/uploadedFiles/Physio85/Contents/Emergency_Medical_Care/ Products/Brochures/LP1000_Brochure 20w 20Rechargable 20Battery_3303851_C. pdf, copyright © 2012 Physio-Control, Inc.
LIFEPAK® 1000 除颤器手册第 168 页上的徽标,http://wwwphysio-control.com/uploadedFiles/Physio85/Contents/Emergency_Medical_Care/ Products/Brochures/LP1000_Brochure 20w 20Rechargable 20Battery_3303851_C. pdf, copyright © 2012 Physio-Control, Inc.

Tables 表格

Table on page 84 from Mountaineering: The Freedom of the Hills, 6th Edition, published by Mountaineers Books, Seattle and Quiller Publishing, Shrewsbury 148, copyright © 1997. Illustration and table reprinted with permission of the publisher; Table on page 84 adapted from ‘The 2013/14 catalogue of DMM International’, www.dmmwales.com. Reproduced with permission from DMM International Ltd; Table on page 144 from ‘Electrical Power Annual’ report, December 2013, The United States Energy Information Association Source: U. S. Energy Information Administration (Dec 2013).
登山运动》第 84 页的表格:第 6 版,由西雅图登山者图书公司和什鲁斯伯里 148 号 Quiller 出版社出版,版权所有 © 1997 年。插图和表格经出版商许可转载;第 84 页上的表格改编自 "DMM 国际公司 2013/14 年目录",www.dmmwales.com。经 DMM 国际有限公司许可转载;第 144 页的表格摘自 "电力年报",2013 年 12 月,美国能源信息协会:美国能源信息署(2013 年 12 月)。

Text 文本

Extract on page 54 from manufacture hockey goalkeeping equipment, 8 July 2014, http://www.obo.co.nz/the-o-lab, OBO. Reproduced by permission; Extract on page 70 from ‘What is a Plimsoll line?’, http://oceanservice.noaa.gov/facts/plimsoll-line. html. Source: NOAA’s National Ocean Service; Extract on page 96 from USGC FAQs, http://www.usgs.gov/faq. Source: U.S. Geological Survey Department of the Interior/USGS; Extract on page 114 adapted from ‘Tuning the Marimba Bar and Resonator’ http://lafavre.us/tuning-marimba, copyright © 2007 Jeffrey La Favre; Extract on page 126 from ‘Forensic Glass Comparison: Background Information Used in Data Interpretation’, publication number 09-04 of the Laboratory Division of the Federal Bureau of Investigation, Vol.11, No 2 (Maureen Bottrell),April 2009, Source: Federal Bureau of Investigation, Quantico, Virginia, USA; Extract on page 168 from LIFEPAK® 1000 DEFIBRILLATOR brochure, pp. 56-57, http://www. physiocontrol.com /uploadedFiles/Physio85/Contents/Emergency_Medical_ Care/Products/Brochures/LP1000_Brochure%20w%20Rechargable%20 Battery_3303851_C.pdf, copyright © 2012 Physio-Control, Inc. ; Extract on page 190 from ‘Rover Team Working to Diagnose Electrical Issue’, 2 November 2013, http://www.jpl.nasa.gov/news/news.php?feature=3958, Source: NASA.
第 54 页摘自制造曲棍球守门员设备,2014 年 7 月 8 日,http://www.obo.co.nz/the-o-lab,OBO。经许可转载;摘自 "什么是 Plimsoll 线?",http://oceanservice.noaa.gov/facts/plimsoll-line. html,第 70 页。资料来源:美国国家海洋和大气管理局(NOAANOAA's National Ocean Service;摘自 USGC FAQs 第 96 页,http://www.usgs.gov/faq。来源:美国地质调查局美国地质调查局内政部/美国地质调查局;第 114 页摘录自 "马林巴琴琴杆和谐振器的调音"http://lafavre.us/tuning-marimba,版权 © 2007 年 Jeffrey La Favre;第 126 页摘录自 "法医玻璃比较:数据解释中使用的背景信息",联邦调查局实验室部门第 09-04 号出版物,第 11 卷,第 2 期(Maureen Bottrell),2009 年 4 月,资料来源:联邦调查局,匡提科:美国弗吉尼亚州匡提科联邦调查局;摘自 LIFEPAK® 1000 去纤颤器手册第 168 页,第 56-57 页,http://wwwphysiocontrol.com /uploadedFiles/Physio85/Contents/Emergency_Medical_ Care/Products/Brochures/LP1000_Brochure%20w%20Rechargable%20 Battery_3303851_C.pdf, copyright © 2012 Physio-Control, Inc.; 摘自《漫游者团队努力诊断电气问题》第 190 页,2013 年 11 月 2 日,http://www.jpl.nasa.gov/news/news.php?feature=3958,资料来源:美国国家航空航天局。
Every effort has been made to contact copyright holders of material reproduced in this book. Any omissions will be rectified in subsequent printings if notice is given to the publishers.
我们已尽力与本书所转载资料的版权持有者取得联系。如果出版商收到通知,任何遗漏都将在后续版本中得到纠正。
For Photo and Figure Acknowedgements please see page 214
照片和图表致谢请参见第 214 页

COURSE STRUCTURE … iv 课程结构 ... iv
ABOUT THIS BOOK … vi
关于本书 ... vi

PRACTICAL SKILLS … viii 实践技能 ... viii
ASSESSMENT OVERVIEW … x x x\mathbf{x}
评估概述 ... x x x\mathbf{x}

WORKING AS A PHYSICIST … 2
担任物理学家...... 2

TOPIC 1 … 8 主题 1 ... 8
TOPIC 2 … 58 主题 2 ... 58
TOPIC 3 … 88 主题 3 ... 88
TOPIC 4 … 148 专题 4 ... 148
MATHS SKILLS … 194 数学技能 ... 194
PREPARING FOR YOUR EXAMS … 200
准备考试...... 200

SAMPLE EXAM ANSWERS … 202
考试答案示例 ... 202

COMMAND WORDS … 205 命令词...... 205
GLOSSARY … 207 术语表 ... 207
INDEX … 211 索引 ... 211

WORKING AS A PHYSICIST 物理学家

1 STANDARD UNITS IN PHYSICS
物理 1 个标准单位

2 ESTIMATION 2 估算

TOPIC 1 MECHANICS 专题 1 力学

1A MOTION 1A 动议
1 VELOCITY AND ACCELERATION
1 速度和加速度

2 MOTION GRAPHS 2 个运动图表
3 ADDING FORCES 15 3 加力 15
4 MOMENTS 17 4 瞬间 17
5 NEWTON’S LAWS 5 牛顿定律
OF MOTION 运动
6 KINEMATICS EQUATIONS 23
6 运动学方程 23

7 RESOLVING VECTORS 26 7 解析向量 26
8 PROJECTILES 28 8 枚射弹 28
THINKING BIGGER: 想得更远
THE BATTLE OF AGRA 30
阿格拉战役 30

EXAM PRACTICE 32 考试练习 32
1B ENERGY 34 1B 能源 34
1 GRAVITATIONAL POTENTIAL AND KINETIC ENERGIES
1 重力势能和动能

36
2 WORK AND POWER 39
2 工作与权力 39

THINKING BIGGER: 想得更远
THE MECHANICS 技术
OF SOCCER 足球
42
EXAM PRACTICE … 44 考试练习 ... 44
1C MOMENTUM 46
1 MOMENTUM 1 力量 48
2 CONSERVATION OF 2 保护
LINEAR MOMENTUM 线动量 50
1C MOMENTUM 46 1 MOMENTUM 48 2 CONSERVATION OF LINEAR MOMENTUM 50| 1C MOMENTUM | 46 | | :--- | :--- | | 1 MOMENTUM | 48 | | 2 CONSERVATION OF | | | LINEAR MOMENTUM | 50 |
THINKING BIGGER: 想得更远
SAVING HOCKEY GOALKEEPERS
拯救曲棍球守门员

EXAM PRACTICE … 56 考试练习 ... 56
TOPIC 2 主题 2
MATERIALS 材料
2A FLUIDS … 58 2a 流体 ... 58
1 FLUIDS, DENSITY AND 1 流体、密度和
UPTHRUST … 60 推力 ... 60
2 FLUID MOVEMENT … 63
2 流体运动 ... 63

3 VISCOSITY … 65 3 粘度 ... 65
4 TERMINAL VELOCITY … 67
4 终点速度 ... 67

THINKING BIGGER: 想得更远
THE PLIMSOLL LINE … 70
普利姆索尔线...... 70

EXAM PRACTICE … 72 考试练习 ... 72
2B SOLID MATERIAL 2b 固体材料
PROPERTIES … 74 属性 ... 74
1 HOOKE’S LAW … 76
1 胡克定律...... 76

2 STRESS, STRAIN AND 2 应力、应变和
THE YOUNG MODULUS … 79
3 STRESS-STRAIN GRAPHS … 81
3 应力应变图 ... 81

THINKING BIGGER 大处着眼
GET ROPED IN … 84
陷入困境...... 84

EXAM PRACTICE … 86 考试练习 ... 86

TOPIC 3
WAVES AND PARTICLE NATURE OF LIGHT
主题 3 光的波粒性质

3A BASIC WAVES 88 3a 基本波 88
1 WAVE BASICS 90 1 波基本知识 90
2 WAVE TYPES 93 2 种波形 93
THINKING BIGGER: 想得更远
EARTHQUAKE 地震
96
EXAM PRACTICE … 98 考试练习 ... 98
3B THE BEHAVIOUR 3b 行为
OF WAVES … 100 波浪...... 100
1 WAVE PHASE AND 1 个波相和
SUPERPOSITION … 102 叠加...... 102
2 STATIONARY WAVES … 105
2 个静止波 ... 105

3 DIFFRACTION … 108 3 衍射 ... 108
4 WAVE INTERFERENCE … 111
4 波干扰...... 111

THINKING BIGGER 大处着眼
THE MARIMBA … 114 马林巴琴...... 114
EXAM PRACTICE … 116 考试练习 ... 116
3C MORE WAVE 3C 更多波浪
PROPERTIES OF LIGHT … 118
光的特性...... 118

1 REFRACTION … 120 1 次折射 ... 120
2 TOTAL INTERNAL 共 2 个内部
REFLECTION … 122 反思 ... 122
3 POLARISATION … 124 3 极化 ... 124
THINKING BIGGER: 想得更远
GLASS FORENSICS … 126 玻璃取证 ... 126
EXAM PRACTICE … 128 考试练习 ... 128

3D QUANTUM PHYSICS 3D 量子物理学

1 WAVE-PARTICLE 1 波粒
DUALITY 双重性
2 THE PHOTOELECTRIC EFFECT
2 光电效应

3 ELECTRON DIFFRACTION AND INTERFERENCE
3 电子衍射和干涉

4 ATOMIC ELECTRON ENERGIES
4 原子电子能量
THINKING BIGGER: 想得更远
SOLAR CELLS TO POWER 太阳能电池供电
THE USA? 美国?
EXAM PRACTICE 考试练习
130 132 135 138
TOPIC 4 ELECTRIC CIRCUITS
专题 4 电路

4A ELECTRICAL QUANTITIES 4a 电气量

1 ELECTRIC CURRENT 1 电流
2 ELECTRICAL ENERGY TRANSFER
2 电能传输

3 CURRENT AND VOLTAGE RELATIONSHIPS
3 电流和电压关系

156
4 RESISTIVITY … 159 4 电阻率 ... 159
5 CONDUCTION AND 5 传导和
RESISTANCE … 161 阻力...... 161
6 SEMICONDUCTORS … 164 6 半导体...... 164
THINKING BIGGER: 想得更远
SHOCKING STUFF … 168 令人震惊的东西...... 168
EXAM PRACTICE … 170 考试练习 ... 170
4B COMPLETE 4B 已完成
ELECTRICAL CIRCUITS … 172
电路...... 172

1 SERIES AND PARALLEL 1 串联和并联
CIRCUITS … 174 电路...... 174
2 ELECTRICAL CIRCUIT 2 个电路
RULES … 178 规则 ... 178
3 POTENTIAL DIVIDERS … 180
3 个潜在分隔符 ... 180

4 EMF AND INTERNAL 4 EMF 和内部
RESISTANCE … 184 阻力...... 184
5 POWER IN ELECTRIC 5 电力
CIRCUITS … 186 电路...... 186
THINKING BIGGER: 想得更远
CURIOUS VOLTAGE DROP … 190
好奇的电压降 ... 190

EXAM PRACTICE … 192 考试练习 ... 192
MATHS SKILLS … 194 数学技能 ... 194
PREPARING FOR YOUR 准备您的
EXAMS … 200 考试 ... 200
SAMPLE EXAM ANSWERS … 202
考试答案示例 ... 202

COMMAND WORDS … 205 命令词...... 205
GLOSSARY … 207 术语表 ... 207
INDEX … 211 索引 ... 211

ABOUT THIS BOOK 关于本书

This book is written for students following the Pearson Edexcel International Advanced Subsidiary (IAS) Physics specification. This book covers the full IAS course and the first year of the International A Level (IAL) course.
本书是为学习培生爱德思国际高级中等(IAS)物理课程的学生编写的。本书涵盖整个 IAS 课程和国际 A Level (IAL) 课程的第一年。
The book contains full coverage of IAS units (or exam papers) 1 and 2. Each unit in the specification has two topic areas. The topics in this book, and their contents, fully match the specification. You can refer to the Assessment Overview on page X X XX for further information. Students can prepare for the written Practical Skills Paper (unit 3) by using the IAL Physics Lab Book (see page viii of this book).
本书涵盖了国际会计准则单元(或试卷)1 和 2 的全部内容。规范中的每个单元都有两个主题领域。本书中的题目及其内容完全符合考试说明。有关详细信息,请参阅 X X XX 页上的 "评估概述"。学生可以使用IAL物理实验手册(参见本书第viii页)准备实践技能书面试卷(第3单元)。
Each Topic is divided into chapters and sections to break the content down into manageable chunks. Each section features a mix of learning and activities.
每个主题都分为章节,将内容分解成易于管理的小块。每个部分都包含学习和活动。
Learning objectives 学习目标
Each chapter starts with a list of key assessment objectives.
每章开头都列出了主要评估目标。

1 A 1 VELOCITY AND ACGELERATION
1 a 1 速度和加速度
Mowemenn is fundamental to the denctioning of our univesse. Whetber you are rurring to catch a
Mowemenn 是我们学校的根本。如果您想赶上一个
RATE OF MOVEMENT 运动速度
One of the simplest thans we can measure is how tas an abject is moving You can cakculate an arestain distance
我们可以测量的最简单的方法之一就是物体移动的速度。
Howews the calculstion for powed will only tell you how fast an nbigect is moring Often it is also
功率的计算方法只能告诉您晶体的移动速度,但它还能告诉您晶体的移动速度。
OR v = s t v = Δ s M v = s t v = Δ s M quad^(v=(s)/(t))v=(Delta s)/(M)\quad{ }^{v=\frac{s}{t}} \mathrm{v}=\frac{\Delta s}{M}  v = s t v = Δ s M v = s t v = Δ s M quad^(v=(s)/(t))v=(Delta s)/(M)\quad{ }^{v=\frac{s}{t}} \mathrm{v}=\frac{\Delta s}{M}
the messurement is reseredet to os a a colalar quasunity The
将测量值重新设置为柱状准线。

scalar. aistarce is a scalar and depplacement is a vectoc.
aistarce 是一个标量,而 depplacement 是一个向量。

Specification reference The exact specification references covered in the section are provided.
规范参考 本节所涉及的确切规范参考均已提供。

Subject vocabulary 主题词汇
Key terms are highlighted in blue in the text. Clear definitions are provided at the end of each section for easy reference, and are also collated in a glossary at the back of the book.
关键术语在正文中以蓝色标出。每节末尾都提供了清晰的定义,以方便读者参考,同时还在书后的词汇表中进行了整理。

Exam hints 考试提示

Tips on how to answer examstyle questions and guidance for exam preparation. Worked examples also show you how to work through questions and set out calculations.
提示如何回答考试类型的问题,并提供备考指导。工作示例还向您展示了如何处理问题和进行计算。

Checkpoint 检查点

Questions at the end of each section check understanding of the key learning points in each chapter.
每节末尾的问题可检查对每章学习要点的理解程度。

These help you focus your learning and avoid common errors.
这有助于您集中精力学习,避免常见错误。

Did you know? 你知道吗?
Interesting facts help you to remember the key concepts.
有趣的事实有助于您记住关键概念。
Your learning, chapter by chapter, is always put in context:
您所学到的每一章内容,都会与实际情况相结合:
  • Links to other areas of Physics include previous knowledge that is built on in the topic, and future learning that you will cover later in your course.
    与物理学其他领域的联系包括在本专题中建立起来的先前知识,以及您将在课程后期学习的未来知识。
  • A checklist details maths knowledge required. If you need to practise these skills, you can use the Maths Skills reference at the back of the book as a starting point.
    核对表详细列出了所需的数学知识。如果您需要练习这些技能,可以将书后的数学技能参考作为起点。

TOPIC 1 MECHANICS 专题 1 力学

1A MOTION 1A 动议

MathS sKILL FOR THIS CHAPTER
本章数学任务

Unit of messuremem ieg are nemoan n n nn
信息管理系统的单位是 nemoan n n nn

1A THINKING BIGGER 1a 想得更远
THE BATTLE OF AGRA 阿格拉战役

Thinking Bigger 大处着眼

At the end of each topic, there is an opportunity to read and work with real-life research and writing about science. The activities help you to read real-life material that’s relevant to your course, analyse how scientists write, think critically and consider how different aspects of your learning piece together.
在每个主题的最后,都有机会阅读和处理现实生活中的科学研究和写作。这些活动有助于您阅读与课程相关的真实材料,分析科学家是如何写作的,进行批判性思考,并考虑如何将学习的不同方面结合起来。

Skills 技能

These sections will help you develop transferable skills, which are highly valued in further study and the workplace.
这些课程将帮助你培养可迁移的技能,这些技能在继续深造和工作中都非常重要。

Exam Practice 考试练习

Exam-style questions at the end of each chapter are tailored to the Pearson Edexcel specification to allow for practice and development of exam writing technique. They also allow for practice responding to the command words used in the exams (see the command words glossary at the back of this book).
每章末尾的考试题型均根据培生爱德思考试说明量身定制,便于练习和提高考试写作技巧。此外,还可以练习如何应对考试中使用的指令词(参见本书后面的指令词词汇表)。

1A EXAM PRACTICE 1a 考试练习

PRACTICAL SKILLS 实用技能

Practical work is central to the study of physics. The Pearson Edexcel International Advanced Subsidiary (IAS) Physics specification includes eight Core Practicals that link theoretical knowledge and understanding to practical scenarios.
实践是物理学习的核心。培生爱德思国际高级中等教育(IAS)物理课程规范包括八门核心实践课程,将理论知识和理解与实际情景联系起来。
Your knowledge and understanding of practical skills and activities will be assessed in all examination papers for the IAS Level Physics qualification.
IAS 物理水平资格证书的所有试卷都将评估您对实践技能和活动的认识和理解。
  • Papers 1 and 2 will include questions based on practical activities, including novel scenarios.
    试卷 1 和 2 将包括基于实践活动的问题,包括新颖的情景。
  • Paper 3 will test your ability to plan practical work, including risk management and selection of apparatus.
    试卷 3 将测试你计划实际工作的能力,包括风险管理和仪器选择。
In order to develop practical skills, you should carry out a range of practical experiments related to the topics covered in your course. Further suggestions in addition to the Core Practicals are included below.
为了培养实践技能,您应该进行一系列与课程主题相关的实践实验。以下是除核心实践之外的其他建议。
STUDENT BOOK TOPIC 学生用书主题 IAS CORE PRACTICALS IAS 核心实践
 专题 1 机械
TOPIC 1
MECHANICS
TOPIC 1 MECHANICS| TOPIC 1 | | :--- | | MECHANICS |
CP1

测定自由落体的加速度
Determine the acceleration of a freely-
falling object
Determine the acceleration of a freely- falling object| Determine the acceleration of a freely- | | :--- | | falling object |
 专题 2 材料
TOPIC 2
MATERIALS
TOPIC 2 MATERIALS| TOPIC 2 | | :--- | | MATERIALS |
CP2

使用落球法确定液体的粘度
Use a falling-ball method to determine
the viscosity of a liquid
Use a falling-ball method to determine the viscosity of a liquid| Use a falling-ball method to determine | | :--- | | the viscosity of a liquid |
CP3

测定材料的杨氏模量
Determine the Young modulus of
a material
Determine the Young modulus of a material| Determine the Young modulus of | | :--- | | a material |

专题 3 光的波和粒子本质
TOPIC 3
WAVES AND THE
PARTICLE NATURE
OF LIGHT
TOPIC 3 WAVES AND THE PARTICLE NATURE OF LIGHT| TOPIC 3 | | :--- | | WAVES AND THE | | PARTICLE NATURE | | OF LIGHT |
CP4

使用双光束示波器、信号发生器、扬声器和麦克风测定空气中的声速
Determine the speed of sound in air
using a two-beam oscilloscope, signal
generator, speaker and microphone
Determine the speed of sound in air using a two-beam oscilloscope, signal generator, speaker and microphone| Determine the speed of sound in air | | :--- | | using a two-beam oscilloscope, signal | | generator, speaker and microphone |
CP5

研究长度、张力和单位长度质量对振动弦或振动线频率的影响
Investigate the effects of length,
tension and mass per unit length on the
frequency of a vibrating string or wire
Investigate the effects of length, tension and mass per unit length on the frequency of a vibrating string or wire| Investigate the effects of length, | | :--- | | tension and mass per unit length on the | | frequency of a vibrating string or wire |
CP6

利用衍射光栅确定激光或其他光源发出的光的波长
Determine the wavelength of light from
a laser or other light source using a
diffraction grating
Determine the wavelength of light from a laser or other light source using a diffraction grating| Determine the wavelength of light from | | :--- | | a laser or other light source using a | | diffraction grating |
 专题 4 电路
TOPIC 4
ELECTRIC CIRCUITS
TOPIC 4 ELECTRIC CIRCUITS| TOPIC 4 | | :--- | | ELECTRIC CIRCUITS |
CP7

测定材料的电阻率
Determine the electrical resistivity of
a material
Determine the electrical resistivity of a material| Determine the electrical resistivity of | | :--- | | a material |
CP8

确定电池的电导率和内阻
Determine the e.m.f. and internal
resistance of an electrical cell
Determine the e.m.f. and internal resistance of an electrical cell| Determine the e.m.f. and internal | | :--- | | resistance of an electrical cell |
STUDENT BOOK TOPIC IAS CORE PRACTICALS "TOPIC 1 MECHANICS" CP1 "Determine the acceleration of a freely- falling object" "TOPIC 2 MATERIALS" CP2 "Use a falling-ball method to determine the viscosity of a liquid" CP3 "Determine the Young modulus of a material" "TOPIC 3 WAVES AND THE PARTICLE NATURE OF LIGHT" CP4 "Determine the speed of sound in air using a two-beam oscilloscope, signal generator, speaker and microphone" CP5 "Investigate the effects of length, tension and mass per unit length on the frequency of a vibrating string or wire" CP6 "Determine the wavelength of light from a laser or other light source using a diffraction grating" "TOPIC 4 ELECTRIC CIRCUITS" CP7 "Determine the electrical resistivity of a material" CP8 "Determine the e.m.f. and internal resistance of an electrical cell"| STUDENT BOOK TOPIC | IAS CORE PRACTICALS | | | :---: | :---: | :---: | | TOPIC 1 <br> MECHANICS | CP1 | Determine the acceleration of a freely- <br> falling object | | TOPIC 2 <br> MATERIALS | CP2 | Use a falling-ball method to determine <br> the viscosity of a liquid | | | CP3 | Determine the Young modulus of <br> a material | | TOPIC 3 <br> WAVES AND THE <br> PARTICLE NATURE <br> OF LIGHT | CP4 | Determine the speed of sound in air <br> using a two-beam oscilloscope, signal <br> generator, speaker and microphone | | | CP5 | Investigate the effects of length, <br> tension and mass per unit length on the <br> frequency of a vibrating string or wire | | | CP6 | Determine the wavelength of light from <br> a laser or other light source using a <br> diffraction grating | | TOPIC 4 <br> ELECTRIC CIRCUITS | CP7 | Determine the electrical resistivity of <br> a material | | | CP8 | Determine the e.m.f. and internal <br> resistance of an electrical cell |

UNIT 1 (TOPICS 1 AND 2) MECHANICS AND MATERIALS
第 1 单元(课题 1 和 2)力学与材料

Possible further practicals include:
可能的进一步实践包括
  • Strobe photography or the use of a video camera to analyse projectile motion
    频闪摄影或使用摄像机分析射弹运动
  • Determine the centre of gravity of an irregular rod
    确定不规则杆的重心
  • Investigate the conservation of momentum using light gates and air track
    利用光门和空气轨道研究动量守恒问题
  • Hooke’s law and the Young modulus experiments for a variety of materials
    各种材料的胡克定律和杨氏模量实验

UNIT 2 (TOPICS 3 AND 4)
第 2 单元(专题 3 和 4)

WAVES AND ELECTRICITY 电波
Possible further practicals include:
可能的进一步实践包括
  • Estimating power output of an electric motor
    估算电动机的输出功率
  • Using a digital voltmeter to investigate the output of a potential divider and investigating current/ voltage graphs for a filament bulb, thermistor and diode
    使用数字电压表调查电位分压器的输出,调查灯泡、热敏电阻和二极管的电流/电压图
  • Determining the refractive index of solids and liquids, demonstrating progressive and stationary waves on a slinky
    测定固体和液体的折射率,演示滑条上的渐变波和静止波

In the Student Book, the Core Practical specification and Lab Book references are supplied in the relevant sections.
在学生用书的相关章节中,提供了核心实践规范和实验用书参考资料。

Practical Skills 实用技能

Practical skills boxes explain techniques used in the Core Practicals, and also detail useful skills and knowledge gained in other related investigations.
实践技能框解释了核心实践中使用的技术,还详细介绍了在其他相关调查中获得的有用技能和知识。
This Student Book is accompanied by a Lab Book, which includes instructions and writing frames for the Core Practicals for students to record their results and reflect on their work.
本学生用书附有一本实验用书,其中包括核心实践活动的说明和书写框架,供学生记录结果和反思自己的工作。

Practical skills checklists, practice questions and answers are also provided.
还提供了实用技能检查表、练习题和答案。

The Lab Book records can be used as preparation and revision for the Practical Skills Paper.
实验手册记录可用于实践技能试卷的准备和复习。

ASSESSMENT OVERVIEW 评估概述

The following tables give an overview of the assessment for Pearson Edexcel International Advanced Subsidiary course in Physics. You should study this information closely to help ensure that you are fully prepared for this course and know exactly what to expect in each part of the examination. More information about this qualification, and about the question types in the different papers, can be found on page 200 of this book.
下表概述了培生爱德思国际高级中等物理课程的评估情况。您应仔细研究这些信息,以帮助确保您为本课程做好充分准备,并确切了解考试各部分的要求。有关本资格证书以及不同试卷题型的更多信息,请参阅本书第 200 页。
PAPER / UNIT 1 第 1 单元
 国际航空的发展
PERGENTAGE
OF IAS
PERGENTAGE OF IAS| PERGENTAGE | | :--- | | OF IAS |
 国家
PERGENTAGE
OF IAL
PERGENTAGE OF IAL| PERGENTAGE | | :--- | | OF IAL |
MARK TIME AVAILABILITY

机械与材料书面试卷试卷代码WPH11/01由PearsonEdexcel外部命题和阅卷单级入学
MECHANICS AND MATERIALS
Written exam paper
Paper code
WPH11/01
Externally set and marked by Pearson
Edexcel
Single tier of entry
MECHANICS AND MATERIALS Written exam paper Paper code WPH11/01 Externally set and marked by Pearson Edexcel Single tier of entry| MECHANICS AND MATERIALS | | :--- | | Written exam paper | | Paper code | | WPH11/01 | | Externally set and marked by Pearson | | Edexcel | | Single tier of entry |
40 % 40 % 40%40 \% 20 % 20 % 20%20 \% 80
 1 小时 30 分钟
1 hour
30 minutes
1 hour 30 minutes| 1 hour | | :--- | | 30 minutes |

一月、六月和十月首次评估 :2019 年 1 月
January, June and October
First assessment : January 2019
January, June and October First assessment : January 2019| January, June and October | | :--- | | First assessment : January 2019 |
PAPER / UNIT 2 第 2 单元 PERCENTAGE
 本金百分比
PERCENTAGE
OF IAL
PERCENTAGE OF IAL| PERCENTAGE | | :--- | | OF IAL |
MARK TIME AVAILABILITY

《波浪与电力》书面考试试卷试卷代码WPH12/01 由 PearsonEdexcel 外部命题和阅卷单级考试
WAVES AND ELECTRICITY
Written exam paper
Paper code
WPH12/01
Externally set and marked by Pearson
Edexcel
Single tier of entry
WAVES AND ELECTRICITY Written exam paper Paper code WPH12/01 Externally set and marked by Pearson Edexcel Single tier of entry| WAVES AND ELECTRICITY | | :--- | | Written exam paper | | Paper code | | WPH12/01 | | Externally set and marked by Pearson | | Edexcel | | Single tier of entry |
40 % 40 % 40%40 \% 20 % 20 % 20%20 \% 80
 1 小时 30 分钟
1 hour
30 minutes
1 hour 30 minutes| 1 hour | | :--- | | 30 minutes |

2019 年 1 月、6 月和 10 月首次评估 6 月
January, June and October
First assessment June 2019
January, June and October First assessment June 2019| January, June and October | | :--- | | First assessment June 2019 |
PAPER / UNIT 3 第 3 单元 PERCENTAGE
 本金百分比
PERCENTAGE
OF IAL
PERCENTAGE OF IAL| PERCENTAGE | | :--- | | OF IAL |
MARK TIME AVAILABILITY

物理实践技能 1书面考试试卷代码WPH13/01由 PearsonEdexcel 外部命题和阅卷单级入学
PRACTICAL SKILLS IN PHYSICS 1
Written examination
Paper code
WPH13/01
Externally set and marked by Pearson
Edexcel
Single tier of entry
PRACTICAL SKILLS IN PHYSICS 1 Written examination Paper code WPH13/01 Externally set and marked by Pearson Edexcel Single tier of entry| PRACTICAL SKILLS IN PHYSICS 1 | | :--- | | Written examination | | Paper code | | WPH13/01 | | Externally set and marked by Pearson | | Edexcel | | Single tier of entry |
20 % 20 % 20%20 \% 10 % 10 % 10%10 \% 50
 1 小时 20 分钟
1 hour
20 minutes
1 hour 20 minutes| 1 hour | | :--- | | 20 minutes |

一月、六月和十月首次评估 :2019 年 6 月
January, June and October
First assessment : June 2019
January, June and October First assessment : June 2019| January, June and October | | :--- | | First assessment : June 2019 |
PAPER / UNIT 1 "PERGENTAGE OF IAS" "PERGENTAGE OF IAL" MARK TIME AVAILABILITY "MECHANICS AND MATERIALS Written exam paper Paper code WPH11/01 Externally set and marked by Pearson Edexcel Single tier of entry" 40% 20% 80 "1 hour 30 minutes" "January, June and October First assessment : January 2019" PAPER / UNIT 2 PERCENTAGE "PERCENTAGE OF IAL" MARK TIME AVAILABILITY "WAVES AND ELECTRICITY Written exam paper Paper code WPH12/01 Externally set and marked by Pearson Edexcel Single tier of entry" 40% 20% 80 "1 hour 30 minutes" "January, June and October First assessment June 2019" PAPER / UNIT 3 PERCENTAGE "PERCENTAGE OF IAL" MARK TIME AVAILABILITY "PRACTICAL SKILLS IN PHYSICS 1 Written examination Paper code WPH13/01 Externally set and marked by Pearson Edexcel Single tier of entry" 20% 10% 50 "1 hour 20 minutes" "January, June and October First assessment : June 2019"| PAPER / UNIT 1 | PERGENTAGE <br> OF IAS | PERGENTAGE <br> OF IAL | MARK | TIME | AVAILABILITY | | :---: | :---: | :---: | :---: | :---: | :---: | | MECHANICS AND MATERIALS <br> Written exam paper <br> Paper code <br> WPH11/01 <br> Externally set and marked by Pearson <br> Edexcel <br> Single tier of entry | $40 \%$ | $20 \%$ | 80 | 1 hour <br> 30 minutes | January, June and October <br> First assessment : January 2019 | | PAPER / UNIT 2 | PERCENTAGE | PERCENTAGE <br> OF IAL | MARK | TIME | AVAILABILITY | | WAVES AND ELECTRICITY <br> Written exam paper <br> Paper code <br> WPH12/01 <br> Externally set and marked by Pearson <br> Edexcel <br> Single tier of entry | $40 \%$ | $20 \%$ | 80 | 1 hour <br> 30 minutes | January, June and October <br> First assessment June 2019 | | PAPER / UNIT 3 | PERCENTAGE | PERCENTAGE <br> OF IAL | MARK | TIME | AVAILABILITY | | PRACTICAL SKILLS IN PHYSICS 1 <br> Written examination <br> Paper code <br> WPH13/01 <br> Externally set and marked by Pearson <br> Edexcel <br> Single tier of entry | $20 \%$ | $10 \%$ | 50 | 1 hour <br> 20 minutes | January, June and October <br> First assessment : June 2019 |

ASSESSMENT OBJECTIVES AND WEIGHTINGS
评估目标和权重

ASSESSMENT OBJECTIVE 评估目标 DESCRIPTION % IN IAS 国际会计准则百分比 % IN IA2 % IN IAL
A01 Demonstrate knowledge and understanding of science
展示对科学的认识和理解
34 36 34 36 34-3634-36 29 31 29 31 29-3129-31 32 34 32 34 32-3432-34
A02

(b) 分析和评估科学信息,做出判断并得出结论。
(a) Application of knowledge and understanding of science in
familiar and unfamiliar contexts.
(b) Analysis and evaluation of scientific information to make
judgments and reach conclusions.
(a) Application of knowledge and understanding of science in familiar and unfamiliar contexts. (b) Analysis and evaluation of scientific information to make judgments and reach conclusions.| (a) Application of knowledge and understanding of science in | | :--- | | familiar and unfamiliar contexts. | | (b) Analysis and evaluation of scientific information to make | | judgments and reach conclusions. |
34 36 34 36 34-3634-36 33 36 33 36 33-3633-36 34 36 34 36 34-3634-36
A03

科学实验技能,包括分析和评估数据和方法
Experimental skills in science, including analysis and evaluation
of data and methods
Experimental skills in science, including analysis and evaluation of data and methods| Experimental skills in science, including analysis and evaluation | | :--- | | of data and methods |
20 14 16 14 16 14-1614-16 11 14 11 14 11-1411-14
ASSESSMENT OBJECTIVE DESCRIPTION % IN IAS % IN IA2 % IN IAL A01 Demonstrate knowledge and understanding of science 34-36 29-31 32-34 A02 "(a) Application of knowledge and understanding of science in familiar and unfamiliar contexts. (b) Analysis and evaluation of scientific information to make judgments and reach conclusions." 34-36 33-36 34-36 A03 "Experimental skills in science, including analysis and evaluation of data and methods" 20 14-16 11-14| ASSESSMENT OBJECTIVE | DESCRIPTION | % IN IAS | % IN IA2 | % IN IAL | | :---: | :--- | :---: | :---: | :---: | | A01 | Demonstrate knowledge and understanding of science | $34-36$ | $29-31$ | $32-34$ | | A02 | (a) Application of knowledge and understanding of science in <br> familiar and unfamiliar contexts. <br> (b) Analysis and evaluation of scientific information to make <br> judgments and reach conclusions. | $34-36$ | $33-36$ | $34-36$ | | A03 | Experimental skills in science, including analysis and evaluation <br> of data and methods | 20 | $14-16$ | $11-14$ |

RELATIONSHIP OF ASSESSMENT OBJECTIVES TO UNITS
评估目标与单元的关系

UNIT NUMBER 单位编号 ASSESSMENT OBJECTIVE 评估目标
A01 A02 (a) A02 (b) A03
UNIT 1 单元 1 17 18 17 18 17-1817-18 17 18 17 18 17-1817-18 4.5 5.5 4.5 5.5 4.5-5.54.5-5.5 0.0
UNIT 2 单元 2 17 18 17 18 17-1817-18 17 18 17 18 17-1817-18 4.5 5.5 4.5 5.5 4.5-5.54.5-5.5 0.0
UNIT 3 单元 3 0.0 0.0 0.0 20

国际高级子公司合计
TOTAL FOR INTERNATIONAL
ADVANCED SUBSIDIARY
TOTAL FOR INTERNATIONAL ADVANCED SUBSIDIARY| TOTAL FOR INTERNATIONAL | | :--- | | ADVANCED SUBSIDIARY |
34 36 34 36 34-3634-36 34 36 34 36 34-3634-36 9 11 9 11 9-119-11 20
UNIT NUMBER ASSESSMENT OBJECTIVE A01 A02 (a) A02 (b) A03 UNIT 1 17-18 17-18 4.5-5.5 0.0 UNIT 2 17-18 17-18 4.5-5.5 0.0 UNIT 3 0.0 0.0 0.0 20 "TOTAL FOR INTERNATIONAL ADVANCED SUBSIDIARY" 34-36 34-36 9-11 20| UNIT NUMBER | ASSESSMENT OBJECTIVE | | | | | :---: | :---: | :---: | :---: | :---: | | | A01 | A02 (a) | A02 (b) | A03 | | UNIT 1 | $17-18$ | $17-18$ | $4.5-5.5$ | 0.0 | | UNIT 2 | $17-18$ | $17-18$ | $4.5-5.5$ | 0.0 | | UNIT 3 | 0.0 | 0.0 | 0.0 | 20 | | TOTAL FOR INTERNATIONAL <br> ADVANCED SUBSIDIARY | $34-36$ | $34-36$ | $9-11$ | 20 |

WORKING AS A PHYSICIST 物理学家

Throughout your study of physics, you will develop knowledge and understanding of what it means to work scientifically. You will develop confidence in key scientific skills, such as handling and controlling quantities and units and making estimates. You will also learn about the ways in which the scientific community functions and how society as a whole uses scientific ideas.
在整个物理学习过程中,你将掌握并理解科学工作的含义。你将培养对关键科学技能的信心,如处理和控制数量和单位以及进行估算。您还将了解科学界的运作方式以及整个社会如何利用科学思想。

At the end of each chapter in this book, there is a section called Thinking Bigger. These sections are based broadly on the content of the chapter just completed, but they will also draw on your previous learning from earlier in the course or from your previous studies and point towards future learning and less familiar contexts. The Thinking Bigger sections will also help you to develop transferable skills. By working through these sections, you will:
本书每章末尾都有一节名为 "更广阔的思考 "的内容。这些章节大致基于刚刚完成的章节内容,但也会借鉴你在课程早期或以前学习的知识,并指向未来的学习和不那么熟悉的情境。深入思考 "部分还将帮助你发展可迁移的技能。通过学习这些章节,您将
  • read real-life scientific writing in a variety of contexts and aimed at different audiences
    阅读各种背景下针对不同受众的真实科学文章
  • develop an understanding of how the professional scientific community functions
    了解专业科学界的运作方式
  • learn to think critically about the nature of what you have read
    学会批判性地思考所读内容的性质
  • understand the issues, problems and challenges that may be raised
    了解可能提出的问题、难题和挑战
  • gain practice in communicating information and ideas in an appropriate scientific way
    练习以适当的科学方式交流信息和观点
  • apply your knowledge and understanding to unfamiliar contexts.
    将所学知识和理解运用到陌生的环境中。
You will also gain scientific skills through the hands-on practical work that forms an essential part of your course. As well as understanding the experimental methods of the practicals, it is important that you develop the skills necessary to plan experiments and analyse and evaluate data. Not only are these very important scientific skills, but they will be assessed in your examinations.
您还将通过实践操作获得科学技能,这也是课程的重要组成部分。除了了解实践的实验方法外,培养规划实验、分析和评估数据的必要技能也非常重要。这些不仅是非常重要的科学技能,而且将在考试中进行评估。

MATHS SKILLS FOR PHYSICISTS
物理学家的数学技能

  • Recognise and make use of appropriate units in calculations (e.g. knowing the difference between base and derived units)
    在计算中认识并使用适当的单位(如知道基数单位和导数单位的区别)
  • Estimate results (e.g. estimating the speed of waves on the sea)
    估算结果(如估算海浪的速度)
  • Make order of magnitude calculations (e.g. estimating approximately what an answer should be before you start calculating, including using standard form)
    进行数量级计算(例如,在开始计算前估计出答案的大致值,包括使用标准格式)。
  • Use algebra to rearrange and solve equations (e.g. finding the landing point of a projectile)
    使用代数重新排列和求解方程(如寻找弹丸的落点)
  • Recognise the importance of the straight line graph as an analysis tool for the verification and development of physical laws by experimentation (e.g. choosing appropriate variables to plot to generate a straight line graph with experimental data)
    认识到直线图作为分析工具对通过实验验证和发展物理规律的重要性(例如, 选择适当的变量绘制实验数据以生成直线图)
  • Determine the slope and intercept of a linear graph (e.g. finding acceleration from a velocity-time graph)
    确定线性图的斜率和截距(例如,从速度-时间图中找出加速度)
  • Calculate the area under the line on a graph (e.g. finding the energy stored in a stretched wire)
    计算图表中直线下的面积(例如,计算拉伸电线中储存的能量)
  • Use geometry and trigonometry (e.g. finding components of vectors)
    使用几何和三角法(如求矢量的分量)

What prior knowledge do I need?
我需要哪些先验知识?

  • Understanding and knowledge of physical facts, terminology, concepts, principles and practical techniques
    了解和掌握物理事实、术语、概念、原理和实用技术
  • Applying the concepts and principles of physics, including the applications of physics, to different contexts
    将物理学的概念和原理,包括物理学的应用,应用到不同的情境中
  • Appreciating the practical nature of physics and developing experimental and investigative skills based on the use of correct and safe laboratory techniques
    在使用正确和安全的实验室技术的基础上,了解物理的实用性并发展实验和探究技能
  • Communicating scientific methods, conclusions and arguments using technical and mathematical language
    使用技术和数学语言交流科学方法、结论和论据
  • Consideration of the implications, including benefits and risks, of scientific and technological developments
    审议科技发展的影响,包括益处和风险
  • Understanding how society uses scientific knowledge to make decisions about the implementation of technological developments
    了解社会如何利用科学知识做出实施技术发展的决策

    Understanding of how scientific ideas change over time, and the systems in place to validate these changes
    了解科学思想如何随着时间的推移而变化,以及验证这些变化的现有系统

What will I study later?
我以后要学什么?

  • Knowledge and understanding of further physical facts and terminology, deeper concepts, principles and more complex practical techniques
    掌握和理解更多物理事实和术语、更深层次的概念、原理和更复杂的实用技术
  • Practical skills and techniques for some key physics experiments
    一些关键物理实验的实用技能和技巧
  • How to communicate information and ideas in appropriate ways using appropriate terminology
    如何使用适当的术语,以适当的方式交流信息和观点
  • The implications of science and their associated benefits and risks
    科学的影响及其相关的益处和风险
  • The role of the scientific community in validating new knowledge and ensuring integrity
    科学界在验证新知识和确保完整性方面的作用
  • The ways in which society uses science to inform decision making
    社会利用科学为决策提供信息的方式

1 STANDARD UNITS IN PHYSICS
物理 1 个标准单位

LEARNING OBJECTIVES 学习目标

  • Understand the distinction between base and derived quantities.
    理解基量和导出量之间的区别。

    ■ Understand the idea of a fixed system of units, and explain the SI system.
    理解固定单位制的概念,并解释国际单位制。

BASE AND DERIVED QUANTITIES
基量和导出量

A fig A The international standard kilogram, officially known as the International Prototype Kilogram, is made from a mixture of platinum and iridium and is held at the Bureau International des Poids et Mesures in Paris. All other masses are defined by comparing with this metal cylinder.
A 图 A 国际标准千克的正式名称是 "国际千克原型",由铂和铱的混合物制成,存放在巴黎国际计量局。所有其他质量都是通过与这个金属圆筒进行比较来确定的。

Some measurements we make are of fundamental qualities of things in the universe. For example, the length of a pencil is a fundamental property of the object. Compare this with the pencil’s speed if you drop it. To give a value to the speed, we have to consider a distance moved, and the rate of motion over that distance - we also need to measure time and then do a calculation. You can see that there is a fundamental difference between the types of quantity that are length and speed. We call the length a base unit, whilst the speed is a derived unit. At present, the international scientific community uses seven base units, and from these all other units are derived. Some derived units have their own names. For example, the derived unit of force should be kg m s 2 kg m s 2 kgms^(-2)\mathrm{kg} \mathrm{m} \mathrm{s}^{-2}, but this has been named the newton (N). Other derived units do not get their own name, and we just list the base units that went together in deriving the quantity. For example, speed is measured in m s 1 m s 1 ms^(-1)\mathrm{m} \mathrm{s}^{-1}.
我们所做的一些测量是对宇宙中事物基本特性的测量。例如,铅笔的长度是物体的基本属性。将其与铅笔掉落时的速度进行比较。要给速度取一个值,我们必须考虑移动的距离,以及在这个距离上的运动速度--我们还需要测量时间,然后进行计算。可以看出,长度和速度这两种量之间有着本质的区别。我们称长度为基本单位,而速度则是派生单位。目前,国际科学界使用七种基本单位,所有其他单位都是从这些单位派生出来的。有些派生单位有自己的名称。例如,力的导出单位应该是 kg m s 2 kg m s 2 kgms^(-2)\mathrm{kg} \mathrm{m} \mathrm{s}^{-2} ,但它已被命名为牛顿(N)。其他派生单位则没有自己的名称,我们只是列出了推导出该量的基本单位。例如,速度的单位是 m s 1 m s 1 ms^(-1)\mathrm{m} \mathrm{s}^{-1}
BASIC QUANTITY 基本数量 UNIT NAME 单位名称 UNIT SYMBOL 单位符号
mass 质量 kilogram 公斤 kg 公斤
time 时间 second 附议 s
length 长度 metre 平方米 m
electric current 电流 ampere 安培 A
temperature 温度 kelvin 开尔文 K
amount of substance 物质的量 mole 鼹鼠 mol 
light intensity 光强 candela 蜡烛 cd
BASIC QUANTITY UNIT NAME UNIT SYMBOL mass kilogram kg time second s length metre m electric current ampere A temperature kelvin K amount of substance mole mol light intensity candela cd| BASIC QUANTITY | UNIT NAME | UNIT SYMBOL | | :--- | :--- | :---: | | mass | kilogram | kg | | time | second | s | | length | metre | m | | electric current | ampere | A | | temperature | kelvin | K | | amount of substance | mole | mol | | light intensity | candela | cd |
table A A A\mathbf{A} The base units.
A A A\mathbf{A} 基本单位。

The choice of which quantities are the base ones is somewhat a matter of choice. The scientists who meet to decide on the standard unit system have chosen these seven. You might think that electric current is not a fundamental property, as it is the rate of movement of charge. So it could be derived from measuring charge and time. However, scientists had to pick what was fundamental and they chose current. This means that electric charge is a derived quantity found by multiplying current passing for a given time.
选择哪些量作为基本量在某种程度上是一个选择问题。开会决定标准单位制的科学家们选择了这七个量。你可能会认为电流不是基本性质,因为它是电荷的运动速度。因此,它可以通过测量电荷和时间得出。然而,科学家们必须选择什么是基本性质,他们选择了电流。这就意味着,电荷是通过乘以一定时间内通过的电流而得到的一个导出量。

SI UNITS SI 单位

For each of the base units, a meeting is held every four or six years of the General Conference on Weights and Measures, under the authority of the Bureau International des Poids et Mesures in Paris. At this meeting, they either alter the definition, or agree to continue with the current definition. As we learn more and more about the universe, these definitions are gradually moving towards the fundamental constants of nature.
对于每个基本单位,在巴黎国际计量局的领导下,计量大会每四年或六年举行一次会议。在这次会议上,他们要么修改定义,要么同意继续沿用当前的定义。随着我们对宇宙的了解越来越多,这些定义也逐渐趋向于自然界的基本常数。
A fig B A standard metre, made to be exactly the length that light could travel in 1 / 299792458 1 / 299792458 1//2997924581 / 299792458 of a second.
A 无花果 B 标准米,其长度正好是光在 1 / 299792458 1 / 299792458 1//2997924581 / 299792458 秒内所能传播的长度。
The current definition of each of the seven base units is listed below:
七个基本单位的现行定义如下:
  • The kilogram is the unit of mass; it is equal to the mass of the International Prototype Kilogram, as in fig A A A\mathbf{A}.
    千克是质量单位;它等于国际千克原型的质量,如图 A A A\mathbf{A} 所示。
  • The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
    其次是与铯-133 原子基态两个超频级之间的转变相对应的辐射持续时间 9192631770 个周期。
  • The metre is the length of the path travelled by light in vacuum
    米是光在真空中所走路径的长度
  • during a time interval of 1 299792458 1 299792458 (1)/(299792458)\frac{1}{299792458} of a second (see fig B).
    1 299792458 1 299792458 (1)/(299792458)\frac{1}{299792458} 秒的时间间隔内(见图 B)。
  • The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2 × 10 7 2 × 10 7 2xx10^(-7)2 \times 10^{-7} newton per metre of length.
    安培是这样一个恒定电流:如果在两根无限长、圆形截面可忽略不计、相距 1 米的平行直导体中保持恒定电流,并将其放置在真空中,则在这两根导体之间产生的力等于 2 × 10 7 2 × 10 7 2xx10^(-7)2 \times 10^{-7} 每米长度上的牛顿。
  • The kelvin, unit of thermodynamic temperature, is the fraction 1 273.16 1 273.16 (1)/(273.16)\frac{1}{273.16} of the thermodynamic temperature of the triple point of water.
    开尔文是热力学温度单位,是水的三相点热力学温度的 1 273.16 1 273.16 (1)/(273.16)\frac{1}{273.16} 分数。
  • The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon-12. (When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles or specified groups of such particles.)
    摩尔是一个系统的物质的量,它包含的基本实体的数量与 0.012 千克碳-12 中原子的数量相等。(在使用摩尔时,必须指明基本实体,可以是原子、分子、离子、电子、其他微粒或这些微粒的特定组)。

EXAM HINT 考试提示

Table A has the complete list of SI base units. You will not be asked questions about the candela in the exam.
表 A 列出了国际单位制基本单位的完整列表。考试中不会问到有关坎德拉的问题。

LEARNING TIP 学习提示

‘Metrology’ is the study of the science of measurement, and ‘metrics’ refers to ways of standardising measuring techniques.
计量学 "是对测量科学的研究,而 "度量衡 "指的是将测量技术标准化的方法。

DERIVED UNITS 衍生单位

In table B you will see many of the derived units that we will study in this book, but this is only a list of those that have their own name.
在表 B 中,您将看到我们将在本书中学习的许多派生单位,但这只是有自己名称的派生单位的列表。
 导出数量
DERIVED
QUANTITY
DERIVED QUANTITY| DERIVED | | :--- | | QUANTITY |
UNIT NAME 单位名称 UNIT SYMBOL 单位符号
 基本单位当量
BASE UNITS
EQUIVALENT
BASE UNITS EQUIVALENT| BASE UNITS | | :---: | | EQUIVALENT |
force 强逼 newton 牛顿 N kg m s 2 kg m s 2 kgms^(-2)\mathrm{kg} \mathrm{m} \mathrm{s}^{-2}
energy (work) 能量 joule 焦耳 J kg m 2 s 2 kg m 2 s 2 kgm^(2)s^(-2)\mathrm{kg} \mathrm{m}^{2} \mathrm{~s}^{-2}
power 权力 watt 功率 W W WW kg m 2 s 3 kg m 2 s 3 kgm^(2)s^(-3)\mathrm{~kg} \mathrm{~m}^{2} \mathrm{~s}^{-3}
frequency 频率 hertz 赫兹 Hz 赫兹 s 1 s 1 s^(-1)\mathrm{s}^{-1}
charge 收费 coulomb 寇仑 C As 由于
voltage 电压 volt 伏特 V V VV kg m 2 s 3 A 1 kg m 2 s 3 A 1 kgm^(2)s^(-3)A^(-1)\mathrm{~kg} \mathrm{~m}^{2} \mathrm{~s}^{-3} \mathrm{~A}^{-1}
resistance 阻力 ohm 欧姆 Ω Ω Omega\Omega kg m 2 s 3 A 2 kg m 2 s 3 A 2 kgm^(2)s^(-3)A^(-2)\mathrm{kg} \mathrm{m}^{2} \mathrm{~s}^{-3} \mathrm{~A}^{-2}
"DERIVED QUANTITY" UNIT NAME UNIT SYMBOL "BASE UNITS EQUIVALENT" force newton N kgms^(-2) energy (work) joule J kgm^(2)s^(-2) power watt W kgm^(2)s^(-3) frequency hertz Hz s^(-1) charge coulomb C As voltage volt V kgm^(2)s^(-3)A^(-1) resistance ohm Omega kgm^(2)s^(-3)A^(-2)| DERIVED <br> QUANTITY | UNIT NAME | UNIT SYMBOL | BASE UNITS <br> EQUIVALENT | | :--- | :---: | :---: | :---: | | force | newton | N | $\mathrm{kg} \mathrm{m} \mathrm{s}^{-2}$ | | energy (work) | joule | J | $\mathrm{kg} \mathrm{m}^{2} \mathrm{~s}^{-2}$ | | power | watt | $W$ | $\mathrm{~kg} \mathrm{~m}^{2} \mathrm{~s}^{-3}$ | | frequency | hertz | Hz | $\mathrm{s}^{-1}$ | | charge | coulomb | C | As | | voltage | volt | $V$ | $\mathrm{~kg} \mathrm{~m}^{2} \mathrm{~s}^{-3} \mathrm{~A}^{-1}$ | | resistance | ohm | $\Omega$ | $\mathrm{kg} \mathrm{m}^{2} \mathrm{~s}^{-3} \mathrm{~A}^{-2}$ |
table B Some well known derived units.
表 B 一些著名的衍生单位

POWER PREFIXES 电源前缀

Sometimes the values we have to work with for some quantities mean that the numbers involved are extremely large or small. For example, the average distance from the Earth to the sun, measured in metres, is 150000000000 m . Scientists have made an easier system for writing such large values by adding a prefix to the unit which tells us that it has been multiplied by a very large or very small amount. In the Earth orbit example, the distance is equivalent to 150 billion metres, and the prefix giga- means multiply by a billion. So the Earth-sun distance becomes 150 gigametres, or 150 Gm .
有时,我们必须使用某些量的数值,这意味着所涉及的数字非常大或非常小。例如,地球到太阳的平均距离是 150000000000 米。科学家们为书写这样大的数值提供了一种更简便的方法,即在单位前加上一个前缀,告诉我们该单位乘以一个非常大或非常小的数。在地球轨道的例子中,距离相当于 1500 亿米,前缀 giga- 表示乘以 10 亿。因此,地日距离就变成了 150 千兆米,或 150 Gm。
FACTOR NAME SYMBOL FACTOR NAME SYMBOL
10 1 10 1 10^(1)10^{1} deca-  da 10 1 10 1 10^(-1)10^{-1} deci-  d
10 2 10 2 10^(2)10^{2} hecto- 全株 h 10 2 10 2 10^(-2)10^{-2} centi-  c
10 3 10 3 10^(3)10^{3} kilo- 千克 k 10 3 10 3 10^(-3)10^{-3} milli-  m
10 6 10 6 10^(6)10^{6} mega-  M 10 6 10 6 10^(-6)10^{-6} micro- 微型 μ μ mu\mathrm{\mu}
10 9 10 9 10^(9)10^{9} giga- 十亿 G 10 9 10 9 10^(-9)10^{-9} nano- 纳米 n
10 12 10 12 10^(12)10^{12} tera-  T 10 12 10 12 10^(-12)10^{-12} pico-  P
10 15 10 15 10^(15)10^{15} peta-  P 10 15 10 15 10^(-15)10^{-15} femto- 女性 f
10 18 10 18 10^(18)10^{18} exa-  E 10 18 10 18 10^(-18)10^{-18} atto- 阿图 a
10 21 10 21 10^(21)10^{21} zetta- Z 10 21 10 21 10^(-21)10^{-21} zepto- z
10 24 10 24 10^(24)10^{24} yotta- Y 10 24 10 24 10^(-24)10^{-24} yocto- 溜溜球 y
FACTOR NAME SYMBOL FACTOR NAME SYMBOL 10^(1) deca- da 10^(-1) deci- d 10^(2) hecto- h 10^(-2) centi- c 10^(3) kilo- k 10^(-3) milli- m 10^(6) mega- M 10^(-6) micro- mu 10^(9) giga- G 10^(-9) nano- n 10^(12) tera- T 10^(-12) pico- P 10^(15) peta- P 10^(-15) femto- f 10^(18) exa- E 10^(-18) atto- a 10^(21) zetta- Z 10^(-21) zepto- z 10^(24) yotta- Y 10^(-24) yocto- y| FACTOR | NAME | SYMBOL | FACTOR | NAME | SYMBOL | | :---: | :---: | :---: | :---: | :---: | :---: | | $10^{1}$ | deca- | da | $10^{-1}$ | deci- | d | | $10^{2}$ | hecto- | h | $10^{-2}$ | centi- | c | | $10^{3}$ | kilo- | k | $10^{-3}$ | milli- | m | | $10^{6}$ | mega- | M | $10^{-6}$ | micro- | $\mathrm{\mu}$ | | $10^{9}$ | giga- | G | $10^{-9}$ | nano- | n | | $10^{12}$ | tera- | T | $10^{-12}$ | pico- | P | | $10^{15}$ | peta- | P | $10^{-15}$ | femto- | f | | $10^{18}$ | exa- | E | $10^{-18}$ | atto- | a | | $10^{21}$ | zetta- | Z | $10^{-21}$ | zepto- | z | | $10^{24}$ | yotta- | Y | $10^{-24}$ | yocto- | y |
table C Prefixes used with SI units.
表 C 与国际单位制单位一起使用的前缀。

CHECKPOINT 检查点

SKILLS PROBLEM SOLVING 解决问题的技能

  1. Refer to table B and answer the following questions:
    请参考表 B 并回答下列问题:

    (a) Pick any quantity that you have studied before and explain how its base unit equivalent is shown.
    (a) 任选一个你以前学过的量,并解释其基本单位等量如何表示。

    (b) All of the derived quantity units are named after scientists. Compare their names and abbreviations. What do you notice?
    (b) 所有衍生量单位都以科学家的名字命名。比较它们的名称和缩写。您发现了什么?
  2. Write the following in standard form:
    用标准格式写出下面的内容:

    (a) 9.2 GW (a) 9.2 千兆瓦
    © 6400 km © 6400 公里
    (b) 43 mm (b) 43 毫米
    (d) 44 ns. (d) 44 ns。
  3. Write the following using an appropriate prefix and unit symbol:
    用适当的前缀和单位符号写出下面的内容:

    (a) 3600000 joules (a) 3600000 焦耳
    © 10 millionths of an ampere
    10 百万分之一安培

    (b) 31536000 seconds (b) 31536000 秒
    (d) 105000 hertz. (d) 105000 赫兹。

2 ESTIMATION 2 估算

LEARNING OBJECTIVES 学习目标

Estimate values for physical quantities. Use your estimates to solve problems.
估算物理量的数值。利用估算值解决问题。

ORDER OF MAGNITUDE 数量级

In physics, it can be very helpful to be able to make approximate estimates of values to within an order of magnitude. This means that the power of ten of your estimate is the same as the true value. For example, you are the same height as the ceiling in your classroom, if we consider the order of magnitude. The ceiling may be twice your height, but it would need to be ten times bigger to reach the next order of magnitude.
在物理学中,能够对一个数量级内的数值进行近似估计是非常有帮助的。这意味着您估计值的十次方与真实值相同。例如,如果我们考虑数量级,你的身高与教室的天花板相同。天花板可能是你身高的两倍,但要达到下一个数量级,天花板需要大十倍。

This is made clearer if we express all values in standard form and then compare the power of ten. You are likely to be a thousand times taller than an ant, so we would say you are three orders of magnitude larger.
如果我们用标准形式表示所有数值,然后比较十的幂次,这一点就更清楚了。你可能比一只蚂蚁高一千倍,所以我们可以说你比蚂蚁大三个数量级。

typical ant height: 1.7 mm = 1.7 × 10 3 m 1.7 mm = 1.7 × 10 3 m 1.7mm=1.7 xx10^(-3)m1.7 \mathrm{~mm}=1.7 \times 10^{-3} \mathrm{~m}
典型的蚂蚁高度: 1.7 mm = 1.7 × 10 3 m 1.7 mm = 1.7 × 10 3 m 1.7mm=1.7 xx10^(-3)m1.7 \mathrm{~mm}=1.7 \times 10^{-3} \mathrm{~m}

typical human height: 1.7 m = 1.7 × 10 m 1.7 m = 1.7 × 10 m 1.7m=1.7 xx10^(@)m1.7 \mathrm{~m}=1.7 \times 10^{\circ} \mathrm{m}
典型的人类身高: 1.7 m = 1.7 × 10 m 1.7 m = 1.7 × 10 m 1.7m=1.7 xx10^(@)m1.7 \mathrm{~m}=1.7 \times 10^{\circ} \mathrm{m}

fig A We are three orders of magnitude taller than an ant.
图 A 我们比蚂蚁高三个数量级。

In many situations, physicists are not interested in specific answers, as circumstances can vary slightly and then the specific answer is incorrect. An order of magnitude answer will always be correct, unless you change the initial conditions by more than an order of magnitude. So a physicist could easily answer the question ‘What is the fastest speed of a car?’ because we don’t really want to know the exact true value. To give an exact answer would depend on knowing the model of car, and the weather and road conditions, and this answer would only be correct for that car on that day. By estimating important quantities, like a typical mass for cars, we can get an approximate - order of magnitude - answer. The reason for doing so would be that it allows us to develop ideas as possible or impossible. Also it helps us focus on developing the ideas along lines that will eventually be feasible when we get to developing a specific solution. This reduces time and money wasted by following ideas that are impossible. It also helps us quickly notice any miscalculations in an answer to a question. If we used an equation to calculate the answer to the fastest speed of a particular car in particular conditions, and the answer came out as 300000000 metres per second (the speed of light), we would immediately know that the answer is wrong, and re-check the calculation.
在很多情况下,物理学家对具体的答案并不感兴趣,因为情况可能稍有不同,那么具体的答案就是不正确的。数量级答案总是正确的,除非初始条件的变化超过一个数量级。因此,物理学家可以很容易地回答 "汽车的最快速度是多少 "这个问题,因为我们并不想知道确切的真实值。要给出准确的答案,就必须知道汽车的型号、天气和路况,而且这个答案只对当天的那辆车正确。通过估计重要的量,比如汽车的典型质量,我们可以得到一个近似的数量级的答案。这样做的原因是,它可以让我们提出可能或不可能的想法。同时,这也有助于我们在开发具体解决方案时,专注于按照最终可行的思路来开发想法。这就减少了因遵循不可能的想法而浪费的时间和金钱。它还能帮助我们迅速发现问题答案中的计算错误。如果我们用一个等式来计算某辆汽车在特定条件下的最快速度,而得出的答案是每秒 300000000 米(光速),我们就会立即知道答案是错误的,并重新检查计算结果。
 数量级
ORDER OF MAGNITUDE
SCALE
ORDER OF MAGNITUDE SCALE| ORDER OF MAGNITUDE | | :--- | | SCALE |
TYPICAL OBJECT 典型物体
1 × 10 13 m 1 × 10 13 m 1xx10^(13)m1 \times 10^{13} \mathrm{~m} size of the solar system
太阳系大小
1 × 10 11 m 1 × 10 11 m 1xx10^(11)m1 \times 10^{11} \mathrm{~m} size of Earth's orbit around the sun
地球围绕太阳的轨道大小
1 × 10 8 m 1 × 10 8 m 1xx10^(8)m1 \times 10^{8} \mathrm{~m} size of Moon's orbit around Earth
月径
1 × 10 4 m 1 × 10 4 m 1xx10^(4)m1 \times 10^{4} \mathrm{~m} diameter of Manchester 曼彻斯特直径
1 × 10 0 m 1 × 10 0 m 1xx10^(0)m1 \times 10^{0} \mathrm{~m} human height 人高
1 × 10 3 m 1 × 10 3 m 1xx10^(-3)m1 \times 10^{-3} \mathrm{~m} ant height 蚁高
1 × 10 5 m 1 × 10 5 m 1xx10^(-5)m1 \times 10^{-5} \mathrm{~m} biological cell diameter 生物细胞直径
1 × 10 8 m 1 × 10 8 m 1xx10^(-8)m1 \times 10^{-8} \mathrm{~m} wavelength of ultraviolet light
紫外线波长
1 × 10 10 m 1 × 10 10 m 1xx10^(-10)m1 \times 10^{-10} \mathrm{~m} diameter of an atom 原子直径
1 × 10 14 m 1 × 10 14 m 1xx10^(-14)m1 \times 10^{-14} \mathrm{~m} diameter of an atomic nucleus
原子核直径
"ORDER OF MAGNITUDE SCALE" TYPICAL OBJECT 1xx10^(13)m size of the solar system 1xx10^(11)m size of Earth's orbit around the sun 1xx10^(8)m size of Moon's orbit around Earth 1xx10^(4)m diameter of Manchester 1xx10^(0)m human height 1xx10^(-3)m ant height 1xx10^(-5)m biological cell diameter 1xx10^(-8)m wavelength of ultraviolet light 1xx10^(-10)m diameter of an atom 1xx10^(-14)m diameter of an atomic nucleus| ORDER OF MAGNITUDE <br> SCALE | TYPICAL OBJECT | | :--- | :--- | | $1 \times 10^{13} \mathrm{~m}$ | size of the solar system | | $1 \times 10^{11} \mathrm{~m}$ | size of Earth's orbit around the sun | | $1 \times 10^{8} \mathrm{~m}$ | size of Moon's orbit around Earth | | $1 \times 10^{4} \mathrm{~m}$ | diameter of Manchester | | $1 \times 10^{0} \mathrm{~m}$ | human height | | $1 \times 10^{-3} \mathrm{~m}$ | ant height | | $1 \times 10^{-5} \mathrm{~m}$ | biological cell diameter | | $1 \times 10^{-8} \mathrm{~m}$ | wavelength of ultraviolet light | | $1 \times 10^{-10} \mathrm{~m}$ | diameter of an atom | | $1 \times 10^{-14} \mathrm{~m}$ | diameter of an atomic nucleus |
table A Examples of object scales changing with powers of ten.
表 A 物体比例随 10 的幂次变化的示例。

FERMI QUESTIONS 费米问题
A fig B Enrico Fermi was one of the developers of both nuclear reactors and nuclear bombs, along with other work on particle physics, quantum physics and statistical mechanics. He was awarded the 1938 Nobel Prize for Physics for the discovery of new radioactive elements and induced radioactivity.
恩里科-费米是核反应堆和核弹的开发者之一,同时还从事粒子物理学、量子物理学和统计力学方面的工作。他因发现新的放射性元素和诱导放射性而获得 1938 年诺贝尔物理学奖。

Enrico Fermi was an Italian physicist who lived from 1901 to 1954. He was a pioneer of estimation. What have become known as Fermi questions are seemingly specific questions, to which
恩里科-费米是意大利物理学家,1901 年至 1954 年在世。他是估算学的先驱。被称为费米问题的是一些看似具体的问题,其中

only an order of magnitude answer is expected. It is common for the question to appear very difficult, as we do not have enough information to work out the answer. One of Fermi’s most interesting thought experiments was a consideration of whether or not alien life exists. Over a lunch with other scientists in 1950, Fermi surprised the group by asking ‘Where is everybody?’ referring to extraterrestrials. There seems to be no evidence of the existence of alien life. That is still as true today as it was in 1950. However, when Fermi made an estimation of what would be necessary for an extraterrestrial civilisation to travel to visit us, his estimate came out at a much shorter amount of time than the age of our galaxy.
只要求给出一个数量级的答案。由于我们没有足够的信息来计算出答案,因此问题看起来非常困难是很常见的。费米最有趣的思想实验之一是思考外星生命是否存在。1950 年,费米在与其他科学家共进午餐时,惊讶地问道:"大家都去哪儿了?"他指的是外星人。似乎没有证据表明外星生命的存在。今天的情况与 1950 年一样。然而,当费米估算外星文明前往拜访我们所需的时间时,他估算出的时间比银河系的年龄要短得多。

Δ Δ Delta\Delta fig C The Fermi Paradox: even the most conservative estimates of the requirements of exploring the galaxy mean that aliens should reach Earth within ten million years of their life beginning. If they existed, they would be here.
Δ Δ Delta\Delta fig C 费米悖论:即使是对探索银河系的要求最保守的估计,也意味着外星人应该在其生命开始后的一千万年内到达地球。如果他们存在,他们就会在这里。

You need to work out what steps are needed to make an estimation. First, think about what steps you would take to reach an answer, if you could have any information you wanted. Then, when the necessary data is not all available, make an estimate for the missing numbers. Making sensible assumptions is the key to solving Fermi questions.
您需要制定出估算所需的步骤。首先,想一想如果你能得到任何想要的信息,你会采取哪些步骤来得出答案。然后,在所需数据不全的情况下,对缺失的数据进行估算。做出合理的假设是解决费米问题的关键。

WORKED EXAMPLE 工作范例

Probably the most famous example of a Fermi question was this challenge to a class:
费米问题最有名的例子可能就是向全班同学提出的这个挑战:

‘How many piano tuners are there in Chicago?’
芝加哥有多少钢琴调音师?

The only piece of information he provided was that the population of Chicago was 3 million.
他提供的唯一信息是芝加哥人口为 300 万。
Step 1: How many pianos in Chicago?
第一步:芝加哥有多少架钢琴?

If each household is 4 people, then there are:
如果每个家庭有 4 人,那么就有

3000000 4 = 750000 3000000 4 = 750000 (3000000)/(4)=750000\frac{3000000}{4}=750000 households  3000000 4 = 750000 3000000 4 = 750000 (3000000)/(4)=750000\frac{3000000}{4}=750000 住户
If one household in ten owns a piano, then there are:
如果每十户家庭中就有一户拥有钢琴,那么就有

750000 10 = 75000 750000 10 = 75000 (750000)/(10)=75000\frac{750000}{10}=75000 pianos  750000 10 = 75000 750000 10 = 75000 (750000)/(10)=75000\frac{750000}{10}=75000 钢琴
Step 2: How many pianos per piano tuner?
步骤 2:每个钢琴调音师负责多少架钢琴?

Assume each piano needs tuning once a year. Further assume a piano tuner works 200 days a year, and can service 4 pianos a day. Each tuner can service: 200 × 4 = 800 200 × 4 = 800 200 xx4=800200 \times 4=800 pianos.
假设每架钢琴每年需要调音一次。再假设一名钢琴调音师每年工作 200 天,每天可为 4 架钢琴调音。每个调音师可以为 200 × 4 = 800 200 × 4 = 800 200 xx4=800200 \times 4=800 钢琴。
Step 3: How many tuners?
步骤 3:多少个调谐器?

Each piano tuner works with 800 pianos, and there are 75000 pianos in total. So there are: 75000 800 = 94 75000 800 = 94 (75000)/(800)=94\frac{75000}{800}=94 piano tuners.
每个钢琴调音师负责 800 台钢琴,总共有 75000 台钢琴。因此有 75000 800 = 94 75000 800 = 94 (75000)/(800)=94\frac{75000}{800}=94 钢琴调音师。

Your answer to Fermi would be ‘There are 100 piano tuners in Chicago’. This is not expected to be the exactly correct answer, but it will be correct to order of magnitude. We would not expect to find that Chicago has only 10 piano tuners, and it would be very surprising if there were 1000.
你给费米的答案是 "芝加哥有 100 个钢琴调音师"。这不可能是完全正确的答案,但在数量级上是正确的。我们不会想到芝加哥只有 10 个钢琴调音师,如果有 1000 个,那就太令人吃惊了。

CHECKPOINT 检查点

SKILLS ADAPTIVE LEARNING 技能适应性学习

  1. Give an order of magnitude estimate for the following quantities:
    估算下列数量的数量级:

    (a) the height of a giraffe
    (a) 长颈鹿的身高

    (b) the mass of an apple
    (b) 苹果的质量

    © the reaction time of a human
    人的反应时间

    (d) the diameter of a planet
    (d) 行星的直径

    (e) the temperature in this room.
    (e) 该房间的温度。
  2. Answer the following Fermi questions, showing all the steps and the assumptions and estimates you make.
    请回答下列费米问题,并说明所有步骤以及你所做的假设和估计。

    (a) How many tennis balls would fit into a soccer stadium?
    (a) 一个足球场能容纳多少个网球?

    (b) How many atoms are there in your body?
    (b) 你体内有多少原子?

    © How many drops of water are there in a swimming pool?
    © 游泳池里有多少滴水?

    (d) In your lifetime, how much money will you make in total?
    (d) 在你的一生中,你总共能赚多少钱?

    (e) How many Fermi questions could Enrico Fermi have answered whilst flying from Rome to New York?
    (e) 在从罗马飞往纽约的途中,恩里科-费米可以回答多少个费米问题?

TOPIC 1 MECHANICS 专题 1 力学

1A MOTION 1A 动议

How can we calculate how fast a plane is flying, in what direction it is going and how long it will take to reach a certain destination? If you were a pilot, how would you know what force to make the engines produce and where to direct that force so your plane moves to your destination?
我们如何计算飞机的飞行速度、飞行方向以及到达某个目的地所需的时间?如果你是一名飞行员,你如何知道该让发动机产生多大的力,以及该把力引向何处,从而让飞机飞向目的地?

An incredible number of intricate calculations need to be done to enable a successful flight, and the basis for all of them is simple mechanics.
要实现成功的飞行,需要进行大量复杂的计算,而所有计算的基础都是简单的力学。
This chapter explains the multiple movements of objects. It looks at how movement can be described and recorded, and then moves on to explaining why movement happens. It covers velocity and acceleration, including how to calculate these in different situations.
本章解释物体的多种运动。本章首先介绍如何描述和记录运动,然后解释运动发生的原因。它涵盖了速度和加速度,包括如何在不同情况下计算速度和加速度。

We only consider objects moving at speeds that could be encountered in everyday life. At these speeds (much less than the speed of light) Sir Isaac Newton succinctly described three laws of motion. With knowledge of basic geometry, we can identify aspects of movement in each dimension.
我们只考虑以日常生活中可能遇到的速度运动的物体。在这种速度下(远小于光速),艾萨克-牛顿爵士简明扼要地描述了三条运动定律。利用基本几何知识,我们可以确定每个维度中运动的各个方面。

Newton’s laws of motion have been constantly under test by scientists ever since he published them in 1687. Within the constraints established by Einstein in the early twentieth century, Newton’s laws have always correctly described the relationships between data collected. You may have a chance to confirm Newton’s laws in experiments of your own. With modern ICT recording of data, the reliability of such experiments is now much improved over traditional methods.
牛顿的运动定律自 1687 年发表以来,一直不断接受科学家的检验。在爱因斯坦于二十世纪初建立的约束条件下,牛顿定律始终正确地描述了所收集数据之间的关系。你也许有机会在自己的实验中证实牛顿定律。通过现代信息和通信技术记录数据,这类实验的可靠性比传统方法有了很大提高。

MATHS SKILLS FOR THIS CHAPTER
本章的数学技能

  • Units of measurement (e.g. the newton, N N NN )
    测量单位(如牛顿、 N N NN )
  • Using Pythagoras’ theorem, and the angle sum of a triangle (e.g. finding a resultant vector)
    使用勾股定理和三角形的角和(如求结果向量)
  • Using sin, cos and tan in physical problems (e.g. resolving vectors)
    在物理问题中使用 sin、cos 和 tan(如解决矢量问题)
  • Using angles in regular 2D structures (e.g. interpreting force diagrams to solve problems)
    在规则的二维结构中使用角(例如,解释力图来解决问题)
  • Changing the subject of an equation (e.g. re-arranging the kinematics equations)
    改变方程式的主题(例如重新排列运动学方程式)
  • Substituting numerical values into algebraic equations (e.g. calculating the acceleration)
    将数值代入代数方程(如计算加速度)
  • Plotting two variables from experimental or other data, understanding that y = m x + c y = m x + c y=mx+cy=m x+c represents a linear relationship and determining the slope of a linear graph (e.g. verifying Newton’s second law experimentally)
    根据实验数据或其他数据绘制两个变量的图形,理解 y = m x + c y = m x + c y=mx+cy=m x+c 代表线性关系,并确定线性图形的斜率(例如,通过实验验证牛顿第二定律)。
  • Estimating, by graphical methods as appropriate, the area between a curve and the x x xx-axis and realising the physical significance of the area that has been determined (e.g. using a speed-time graph)
    通过适当的图形方法估算曲线与 x x xx 轴之间的面积,并认识到所确定的面积的物理意义(例如使用速度-时间图形)

1A 1 VELOCITY AND AGGELERATION
1a 1 速度和加速度

LEARNING OBJECTIVES 学习目标

Explain the distinction between scalar and vector quantities.
解释标量和矢量的区别。

Distinguish between speed and velocity and define acceleration.
区分速度和速率,定义加速度。
  • Calculate values using equations for velocity and acceleration.
    使用速度和加速度方程计算数值。

Δ Δ Delta\Delta fig A A A\mathbf{A} These runners are accelerating to a high speed.
Δ Δ Delta\Delta A A A\mathbf{A} 这些选手正在高速加速。

LEARNING TIP 学习提示

The upper case Greek letter delta, Δ Δ Delta\Delta, is used in mathematics to indicate a change in a quantity. For example, Δ s Δ s Delta s\Delta s means the change in the displacement of an object, to be used here to calculate the velocity of the object.
希腊文大写字母 delta, Δ Δ Delta\Delta ,在数学中用来表示一个量的变化。例如, Δ s Δ s Delta s\Delta s 表示物体位移的变化,这里用来计算物体的速度。

DID YOU KNOW? 您知道吗?

The froghopper, a 6 mm long insect, can accelerate at 4000 m s 1 4000 m s 1 4000ms^(-1)4000 \mathrm{~m} \mathrm{~s}^{-1}.
蛙蛙是一种 6 毫米长的昆虫,能以 4000 m s 1 4000 m s 1 4000ms^(-1)4000 \mathrm{~m} \mathrm{~s}^{-1} 的速度加速。

LEARNING TIP 学习提示

Vector notation means that vectors are written in bold type to distinguish them from scalar variables.
矢量符号是指用粗体字书写矢量,以区别于标量变量。

Movement is fundamental to the functioning of our universe. Whether you are running to catch a bus or want to calculate the speed required for a rocket to travel to Mars or the kinetic energy of an electron in an X-ray machine, you need to be able to work out how fast things are moving.
运动是宇宙运行的基础。无论你是跑着去赶公共汽车,还是想计算火箭飞往火星所需的速度或 X 射线机器中电子的动能,你都需要能够计算出事物运动的速度。

RATE OF MOVEMENT 运动速度

One of the simplest things we can measure is how fast an object is moving. You can calculate an object’s speed if you know the amount of time taken to move a certain distance:
我们可以测量的最简单的事情之一就是物体移动的速度。如果知道物体移动一定距离所需的时间,就可以计算出物体的速度:
speed ( m s 1 ) = distance ( m ) time ( s ) v = d t  speed  m s 1 =  distance  ( m ) time ( s ) v = d t {:[" speed "(ms^(-1))=(" distance "(m))/(time(s))],[v=(d)/(t)]:}\begin{aligned} \text { speed }\left(\mathrm{m} \mathrm{~s}^{-1}\right) & =\frac{\text { distance }(\mathrm{m})}{\operatorname{time}(\mathrm{s})} \\ v & =\frac{d}{t} \end{aligned}
However, the calculation for speed will only tell you how fast an object is moving. Often it is also vitally important to know in what direction this movement is taking the object. When you include the direction in the information about the rate of movement of an object, this is then known as the velocity. So, the velocity is the rate of change of displacement, where the distance in a particular direction is called the ‘displacement’.
然而,速度计算只能告诉您物体移动的速度。通常,知道物体运动的方向也是非常重要的。如果在物体运动速度的信息中包含方向,这就是速度。因此,速度就是位移的变化率,其中特定方向上的距离称为 "位移"。
velocity ( m s 1 ) = displacement ( m ) time ( s ) v = s t OR v = Δ s Δ t  velocity  m s 1 =  displacement  ( m )  time  ( s ) v = s t  OR  v = Δ s Δ t {:[" velocity "(ms^(-1))=(" displacement "(m))/(" time "(s))],[v=(s)/(t)],[" OR "],[v=(Delta s)/(Delta t)]:}\begin{aligned} & \text { velocity }\left(\mathrm{m} \mathrm{~s}^{-1}\right)=\frac{\text { displacement }(\mathrm{m})}{\text { time }(\mathrm{s})} \\ & v=\frac{s}{t} \\ & \text { OR } \\ & v=\frac{\Delta s}{\Delta t} \end{aligned}
A fig B The displacement due north is only 75 m , whilst the actual distance this athlete has run is 300 m . So the velocity due north is much less than the actual speed.
A 图 B 正北方向的位移只有 75 米,而这名运动员实际跑了 300 米。因此,正北方向的速度远小于实际速度。
A quantity for which the direction must be stated is known as a vector. If direction is not important, the measurement is referred to as a scalar quantity. Therefore, velocity is a vector and speed is a scalar; distance is a scalar and displacement is a vector.
必须说明方向的量称为矢量。如果方向并不重要,测量结果就被称为标量。因此,速度是矢量,速度是标量;距离是标量,位移是矢量。
Scalar and vector quantities are not limited to measurements related to movement. Every measured quantity can be classified to include the direction (vector, e.g. force) or as being sufficiently stated by its magnitude only (scalar, e.g. mass).
标量和矢量并不局限于与运动有关的测量。每个测量量都可分为包括方向(矢量,如力)或仅由其大小充分说明(标量,如质量)的量。

AVERAGE AND INSTANTANEOUS SPEED
平均速度和瞬时速度

In most journeys, it is unlikely that speed will remain constant throughout. As part of his training programme, an athlete in fig A wants to keep a record of his speed for all races. From rest, before the starting gun starts the race, he accelerates to a top speed. However, the race timing will be made from start to finish, and so it is most useful to calculate an average speed over the whole race. Average speed is calculated by dividing the total distance for a journey by the total time for the journey. Thus it averages out the slower and faster parts of the journey, and even includes stops.
在大多数旅程中,速度不可能始终保持不变。作为训练计划的一部分,图 A 中的运动员希望记录下自己所有比赛的速度。在比赛发令枪响之前,他从静止状态加速到最高速度。不过,比赛计时将从起点到终点,因此计算整场比赛的平均速度最为有用。平均速度的计算方法是用总路程除以总时间。因此,它平均了路程中较慢和较快的部分,甚至包括停顿。

Instantaneous speed can be an important quantity, and we will look at how to measure it in the next topic.
瞬时速度是一个重要的量,我们将在下一个主题中探讨如何测量它。
A fig C Most speed checks look at instantaneous speed, but CCTV allows police to monitor average speed over a long distance.
A 无花果 C 大多数车速检查都是检查瞬时车速,但闭路电视可以让警方监测长距离的平均车速。

ACCELERATION 加速度

Acceleration is defined as the rate of change of velocity. Therefore, it must include the direction in which the speed is changing, and so acceleration is a vector quantity. The equation defining acceleration is:
加速度的定义是速度的变化率。因此,它必须包括速度变化的方向,所以加速度是一个矢量。定义加速度的方程为
acceleration ( m s 2 ) = change in velocity ( m s 1 ) time taken to change the velocity ( s )  acceleration  m s 2 =  change in velocity  m s 1  time taken to change the velocity  ( s ) " acceleration "(ms^(-2))=(" change in velocity "(ms^(-1)))/(" time taken to change the velocity "(s))\text { acceleration }\left(\mathrm{m} \mathrm{~s}^{-2}\right)=\frac{\text { change in velocity }\left(\mathrm{m} \mathrm{~s}^{-1}\right)}{\text { time taken to change the velocity }(\mathrm{s})}