Chapter 1 Introduction Chapter 1 Introduction Getting pI repared! Measurement Models Theories and laws Vector and scalar
Chapter 1 Introduction Getting prepared!!! Chapter 1. Introduction • Measurement, Models, Theories and Laws • Vector and Scalar
Chapter 1 Introduction 1-1 Models, theories, and laws(P3) Model: is a kind of mental image of the phenomena in terms of something are familiar with Theory: is broader, more detailed, and attempts to solve a set of phenomena Law: are general statements about how nature behaves. The statement takes the form of a relationship or equation(方程) between quantities(量)
Chapter 1 Introduction 1-1 Models, theories, and laws (P3) Model: is a kind of mental image of the phenomena in terms of something are familiar with. Theory: is broader, more detailed, and attempts to solve a set of phenomena. Law: are general statements about how nature behaves. The statement takes the form of a relationship or equation ( 方 程 ) between quantities (量)
Chapter 1 Introduction 1-2 Measurement and Uncertainty; Significant Figures(P3-5) Physics is based on measurement of physical quantities(物理量,P3 Significant Figures(有效数字): The number of relia bly known digits in a number is called the number of significant figures P4
Chapter 1 Introduction 1-2 Measurement and Uncertainty; Significant Figures(P3-5) Physics is based on measurement of physical quantities (物理量). P3 Significant Figures(有效数字): The number of reliably known digits in a number is called the number of significant figures. P4
Chapter 1 Introduction Scientific notation(科学记数法(p4) Write numbers in“ powers of ten” Mass of the earth: 5,980,000,0000000kg or 5.98x1044kg Diameter of proton(质子) 0.000000000000001m or 10-15m(or 1 E-15 on computers) The advantage is that it allows the number of significant figures to be clearly expressed
Chapter 1 Introduction Mass of the Earth: 5,980,000,000,000,000,000,000,000kg or 5.98x1024kg Diameter of proton（质子）: 0.000000000000001m or 10-15m (or 1 E-15 on computers) The advantage is that it allows the number of significant figures to be clearly expressed. Scientific notation (科学记数法(p4) Write numbers in “powers of ten
Chapter 1 Introduction 1-4 Units, Standards, and the sI System(P5-7) Unit(单位 We measure each physical quantity in its own units(单位) by comparison with a standard.Ps SI System(国际单位制): There are so many physical quantities that it is a problem to organize them. Fortunately, they are not all independent(独立).P7
Chapter 1 Introduction 1-4 Units, Standards, and the SI System (P5-7) Unit (单位): We measure each physical quantity in its own units(单位) by comparison with a standard. P5 SI System (国际单位制): There are so many physical quantities that it is a problem to organize them. Fortunately, they are not all independent （独立）. P7
Chapter 1 Introduction In 1971. the 14 general conference on Weights and Measures, The sI (International System)was adopted It is based on meter, second and kilogram It is also called Metric System(公制) or mKs system Many si(system International) derived units are defined in terms of these base units such as. I watt=1 W=1 kg. m2/S3 The second metric system is CGs(P7), in which the centimeter, gram, and second are the standard units of length, mass and time
Chapter 1 Introduction In 1971, the 14th General Conference on Weights and Measures, The SI (International System) was adopted. It is based on meter, second and kilogram. It is also called Metric System (公制） or MKS system. Many SI (System International) derived units are defined in terms of these base units, such as: 1 watt = 1 W = 1 kg ·m2 / s3 The second metric system is CGS(P7), in which the centimeter, gram, and second are the standard units of length, mass and time
Chapter 1 Introduction Shorthand and some commonly used units (P7) exa E1018 deci 10-1 peta P 1015 centi C 10-2 tera T 1012 10-3 giga G 109 Micro 10-6 Mega M 106 nano n 10 kilo K 103 pico p 10-12 Hecto h 102 femto f 10-15 deka da 10 atto a 10-18
Chapter 1 Introduction exa E 1018 peta P 1015 tera T 1012 giga G 109 Mega M 106 kilo k 103 Hecto h 102 deka da 101 deci d 10-1 centi c 10-2 milli m 10-3 Micro 10-6 nano n 10-9 pico p 10-12 femto f 10-15 atto a 10-18 Shorthand and some commonly used units (P7)
Chapter 1 Introduction Consistent set of units Base quantities基本量: length,time,mass Base units(基本单位): meter; second, kilogram Derivative quantities(导出量):The quantities derived from base quantities such as: velocity, acceleration Derivative units(导出单位): The units derived from base units such as: m/s m/s
Chapter 1 Introduction Base quantities(基本量): length, time, mass. Base units(基本单位): meter, second, kilogram. Derivative quantities( 导 出 量 ): The quantities derived from base quantities such as：velocity， acceleration . Derivative units( 导 出 单 位 ): The units derived from base units such as：m/s m/s2 . Consistent set of units
Chapter 1 Introduction (1) Length(长度P5): One meter is the length of p path traveled by light in a vacuum during a time interval(间隔)of 1/299792458 of a second. P5 (2)Time(时间P6): One second is the time taken by 9192631770 oscillations(振动) of the light emitted by a cesium(铯) 133 atom (3)Mass(质量P6): One kilogram is defined in terms of根据、按照 a particular platinum-iridium(铂铱) cylinder(柱 A) kept near Paris, france. For measurements on an atomic scale, the atomic mass unit, defined in terms of the atom carbon -12. is usually used. 1u=1. 6605402x10-27 kg
Chapter 1 Introduction One meter is the length of path traveled by light in a vacuum during a time interval（间隔） of 1/299792458 of a second. P5 One second is the time taken by 9192631770 oscillations(振动) of the light emitted by a cesium（铯） -133 atom. One kilogram is defined in terms of(根据、按照） a particular platinum-iridium（铂铱） cylinder（柱 体） kept near Paris, France. For measurements on an atomic scale, the atomic mass unit, defined in terms of the atom carbon-12, is usually used. 1u=1.6605402x10-27 kg （1）Length （长度P5）: （2）Time（时间P6） : （3）Mass（质量P6） :
Chapter 1 Introduction 3-1 Vectors and Scalars(P44-45) Scalar(标量): a ordinary algebraic(代数的) quantity that has no direction. (mass, time, temperature, ..) Some scalars are always positive, whereas others such as electric charge can be positive or negative. Vector(矢量): a quantity that has both direction 方向) and magnitude(大小)it( displacement位 移, velocity速度, acceleration加速度, force力 rva and 尸
Chapter 1 Introduction Some scalars are always positive, whereas others such as electric charge can be positive or negative. r v a and F , , Scalar (标量): A ordinary algebraic (代数的) quantity that has no direction. (mass, time, temperature,…) Vector (矢量): A quantity that has both direction (方向) and magnitude (大小) it (displacement 位 移, velocity速度, acceleration加速度, force力). 3-1 Vectors and Scalars (P44-45)