Mechanics

physics, 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, and assumptions can alter and expand our view of the world around us. The study of physics can be divided into six main areas:
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 the speed 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 the behavior 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 to begin 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 vital importance 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.