Fisica

Mechanics
hysics, the most fundamental physical science, is concerned with the basic principles of the Universe. It is the foundation upon which the other sciences— astronomy, biology, chemistry, and geology—are based. The beauty of physics lies in the simplicity of the fundamental physical theories and in the manner in which just a small number of fundamental concepts, equations, andassumptions can alter and expand our view of the world around us. The study of physics can be divided into six main areas:

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1. classical mechanics, which is concerned with the motion of objects that are large relative to atoms and move at speeds much slower than the speed of light; 2. relativity, which is a theory describing objects moving at any speed, even speeds approaching thespeed of light; 3. thermodynamics, which deals with heat, work, temperature, and the statistical behavior of systems with large numbers of particles; 4. electromagnetism, which is concerned with electricity, magnetism, and electromagnetic fields; 5. optics, which is the study of the behavior of light and its interaction with materials; 6. quantum mechanics, a collection of theories connecting thebehavior of matter at the submicroscopic level to macroscopic observations. The disciplines of mechanics and electromagnetism are basic to all other branches of classical physics (developed before 1900) and modern physics (c. 1900–present). The first part of this textbook deals with classical mechanics, sometimes referred to as Newtonian mechanics or simply mechanics. This is an appropriate place tobegin an introductory text because many of the basic principles used to understand mechanical systems can later be used to describe such natural phenomena as waves and the transfer of energy by heat. Furthermore, the laws of conservation of energy and momentum introduced in mechanics retain their importance in the fundamental theories of other areas of physics. Today, classical mechanics is of vitalimportance to students from all disciplines. It is highly successful in describing the motions of different objects, such as planets, rockets, and baseballs. In the first part of the text, we shall describe the laws of classical mechanics and examine a wide range of phenomena that can be understood with these fundamental ideas. I

Liftoff of the space shuttle Columbia. The tragic accident ofFebruary 1, 2003 that took the lives of all seven astronauts aboard happened just before Volume 1 of this book went to press. The launch and operation of a space shuttle involves many fundamental principles of classical mechanics, thermodynamics, and electromagnetism. We study the principles of classical mechanics in Part 1 of this text, and apply these principles to rocket propulsion in Chapter 9.(NASA)
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Physics and Measurement
CHAPTE R OUTLI N E

1.1 Standards of Length, Mass, and Time 1.2 Matter and Model Building 1.3 Density and Atomic Mass 1.4 Dimensional Analysis 1.5 Conversion of Units 1.6 Estimates and Order-ofMagnitude Calculations 1.7 Significant Figures

L The workings of a mechanical clock. Complicated timepieces have been built for centuries in an effort tomeasure time accurately. Time is one of the basic quantities that we use in studying the motion of objects. (elektraVision/Index Stock Imagery)

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Like all other sciences, physics is based on experimental observations and quantitative

measurements. The main objective of physics is to find the limited number of fundamental laws that govern natural phenomena and to use them to developtheories that can predict the results of future experiments. The fundamental laws used in developing theories are expressed in the language of mathematics, the tool that provides a bridge between theory and experiment. When a discrepancy between theory and experiment arises, new theories must be formulated to remove the discrepancy. Many times a theory is satisfactory only under limited conditions; a...