لخّصلي

Apago PDF Enhancer 1 Image copyright Stephen Inglis.Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.1.1 Standards of Length, Mass, and Time 1.2 The Building Blocks of Matter 1.3 Dimensional Analysis 1.4 Uncertainty in Measurement and Significant Figures 1.5 Conversion of Units 1.6 Estimates and Order-of- Magnitude Calculations 1.7 Coordinate Systems 1.8 Trigonometry 1.9 Problem-Solving Strategy Introduction 1 ser62060_01_c01_p001-024.indd 1 8/17/10 2:16 PM Copyright 2010 Cengage Learning.The basic laws of physics involve such physical quantities as force, velocity, volume, and acceleration, all of which can be described in terms of more fundamental quantities.If our fundamental unit of length is defined to be 1.0 meter, for example, and someone familiar with our system of measure- ment reports that a wall is 2.0 meters high, we know that the height of the wall is twice the fundamental unit of length.Editorial review has deemed that any suppressed content does not materially affect the overall learning experience.If the predictions turn out to correspond closely to what is actually observed, then the theory stands, although it remains provisional.In mechanics, it is conventional to use the quantities of length (L), mass (M), and time (T); all other physical quantities can be constructed from these three.Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).All Rights Reserved.

Apago PDF Enhancer
1
Image copyright Stephen Inglis. Used under license from Shutterstock.com
Stonehenge, in southern
England, was built thousands
of years ago to help keep track
of the seasons. At dawn on the
summer solstice the sun can be
seen through these giant stone
slabs.
The goal of physics is to provide an understanding of the physical world by developing the-
ories based on experiments. A physical theory, usually expressed mathematically, describes
how a given physical system works. The theory makes certain predictions about the physical
system which can then be checked by observations and experiments. If the predictions turn
out to correspond closely to what is actually observed, then the theory stands, although it
remains provisional. No theory to date has given a complete description of all physical phe-
nomena, even within a given subdiscipline of physics. Every theory is a work in progress.
The basic laws of physics involve such physical quantities as force, velocity, volume, and
acceleration, all of which can be described in terms of more fundamental quantities. In
mechanics, it is conventional to use the quantities of length (L), mass (M), and time (T); all
other physical quantities can be constructed from these three.
1.1 Standards of Length, Mass, and Time
To communicate the result of a measurement of a certain physical quantity, a unit
for the quantity must be defined. If our fundamental unit of length is defined
to be 1.0 meter, for example, and someone familiar with our system of measure-
ment reports that a wall is 2.0 meters high, we know that the height of the wall is
twice the fundamental unit of length. Likewise, if our fundamental unit of mass is
defined as 1.0 kilogram and we are told that a person has a mass of 75 kilograms,
then that person has a mass 75 times as great as the fundamental unit of mass.
In 1960 an international committee agreed on a standard system of units for
the fundamental quantities of science, called SI (Système International). Its units
of length, mass, and time are the meter, kilogram, and second, respectively.
1.1 Standards of Length, Mass,
and Time
1.2 The Building Blocks of Matter
1.3 Dimensional Analysis
1.4 Uncertainty in Measurement
and Significant Figures
1.5 Conversion of Units
1.6 Estimates and Order-of-
Magnitude Calculations
1.7 Coordinate Systems
1.8 Trigonometry
1.9 Problem-Solving Strategy
Introduction 1
ser62060_01_c01_p001-024.indd 1 8/17/10 2:16 PM
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.