Physical Sciences and Mathematics Commons^™

Physics, Chapter 14: Temperature, Henry Semat, Robert Katz

Robert Katz Publications

Temperature is one of the fundamental concepts of physics. We are all able to recognize that some bodies are hotter than others, but our temperature sense is qualitative rather than quantitative and is capable of only a limited range. The sense of touch can frequently be used to distinguish between hotter and colder objects, provided that these lie in a temperature range consistent with the stability of human tissue. Even within this range the sense of touch is often unreliable as a measure of temperature.

The metal bracket holding a wooden rail may feel much colder to the touch than …

Physics, Chapter 16: Kinetic Theory Of Gases, Henry Semat, Robert Katz

Robert Katz Publications

The behavior of a gas under various conditions of temperature and pressure has already been studied in some detail. When the pressure of a constant mass of gas is not too great, say less than about 2 atm, we find that a gas obeys the following relationships to be discussed.

Physics, Chapter 33: Magnetic Properties Of Matter, Henry Semat, Robert Katz

Robert Katz Publications

Matter is composed of atoms consisting of positively charged nuclei and negative electrons. These electrons occur in shells, and the periodic nature of chemical properties of atoms as the atomic weight increases is a reflection of the fact that the chemical behavior of an atom depends largely upon the number of electrons in the outermost shell. In some parts of the periodic table (see Table 5 of Appendix A), electrons occupy places in an outer shell before an inner shell is completely filled; it is then observed that a number of different elements have very similar chemical properties. The same …

Physics, Chapter 36: Light And Its Measurement, Henry Semat, Robert Katz

Robert Katz Publications

The word light, as commonly used, refers to the radiant energy which produces a visual effect. It was first shown by Maxwell that light is an electromagnetic radiation, propagated with a speed whose value was numerically determined by the relationship between electric and magnetic units.

Physics, Chapter 28: Electrical Conduction In Liquids And Solids, Henry Semat, Robert Katz

Robert Katz Publications

We have seen that electrical conduction in solids is associated with the drift of free electrons in the solid, a process which will be examined in greater detail in Section 28-4. A similar mechanism may be used to account for the conduction of electricity in liquid metals. In other liquids electricity is conducted by the migration of positive and negative ions through the liquid.

Physics, Chapter 46: Nuclear Reactions, Henry Semat, Robert Katz

Robert Katz Publications

One of the most important developments of twentieth-century physics was the formulation of the special theory of relativity. This theory was an outgrowth of the failure of all attempts to show that the motion of the source of light relative to the observer had any effect on the speed of light. It is impossible to account for these experimental findings of Michelson and Morley, and others, on the basis of classical mechanics and electromagnetic theory. In 1905, Albert Einstein put forth the suggestion that all experimental findings would be clarified if it were assumed that the speed of light is …

Physics, Chapter 27: Direct-Current Circuits, Henry Semat, Robert Katz

Robert Katz Publications

When a charged particle traverses a closed path in an electrostatic field in space, the total work done on the particle is zero. The electric field is conservative. Associated with each point in the field, there is a fixed value of the electrical potential.

In a simple circuit consisting of a chemical cell and a resistor, as shown in Figure 27-1, we have seen that the current flows through the resistor from the positive terminal of the cell to the negative terminal of the cell. The positive terminal is at the higher potential, so that the current flows from the …

Physics, Chapter 5: Force And Motion, Henry Semat, Robert Katz

Robert Katz Publications

All of us have many times had the experience of setting a body in motion. If we analyze any of these experiences, we readily recall that in each case some force was required to start the object moving. In throwing a ball, moving a piece of furniture, or pulling a sled, the force needed to start the object moving is supplied by one's muscular effort as a push or a pull. In more complex cases, such as setting a car or an airplane in motion, the analysis, although more complicated, will also show that a force is required to start …

Physics, Chapter 19: Heat Engines, Henry Semat, Robert Katz

Robert Katz Publications

In this chapter we shall consider the physical principles underlying the operations of heat engines because of the intrinsic importance of these principles and because of the part they have played in the development of fundamental physical ideas. Heat engines are designed and built to convert heat into work. In most cases the heat is obtained from the combustion of a common fuel such as coal, oil, gasoline, or natural gas. An important new source of heat that is just beginning to be used, and will be used more extensively in the future, is the mass which is converted into …

Physics, Chapter 18: Transfer Of Heat, Henry Semat, Robert Katz

Robert Katz Publications

The methods by which heat is transmitted can be classified into three distinct types known as convection, conduction, and radiation. In any actual case of heat transmission, a combination of these methods may be operating simultaneously, and the principal problem is to determine the rate at which heat flows from the source at higher temperature to the source at lower temperature.

We may distinguish between the three processes of heat transfer by considering whether a medium is required for the transfer of heat, and whether that medium is at rest or in motion. In the process of conduction, …

Physics, Chapter 34: Alternating Currents, Henry Semat, Robert Katz

Robert Katz Publications

If the current in a resistor varies sinusoidally, as shown in Figure 34-1, the potential difference across the terminals of the resistor will also vary sinusoidally in the same manner, in phase with the current, in accordance with Ohm's law. Writing i for the instantaneous value of the current and v for the instantaneous value of the potential difference, we have v = iR.

Physics, Chapter 23: The Electric Field, Henry Semat, Robert Katz

Robert Katz Publications

We have previously described the gravitational field as one way of thinking about gravitational forces (Section 6-16). If an object of mass m at rest at a point P experienced a force, we could attribute that force to the presence of the gravitational field. In a similar way we may attribute the force experienced by an electric charge at rest at a point P to the presence of an electric field at that point. From the preceding chapter we recognize that the existence of a force ,on a charged particle is due to the presence of other charged particles in …

Physics, Chapter 15: Heat And Work, Henry Semat, Robert Katz

Robert Katz Publications

Until about 1750 the concepts of heat and temperature were not clearly distinguished. The two concepts were thought to be equivalent in the sense that bodies at equal temperatures were thought to "contain" equal amounts of heat. Joseph Black (1728-1799) was the first to make a clear distinction between heat and temperature. Black believed that heat was a form of matter, which subsequently came to be called caloric, and that the change in temperature of a body when caloric was added to it was associated with a property of the body which he called the capacity. Later investigators endowed caloric …

Physics, Chapter 26: The Electric Current, Henry Semat, Robert Katz

Robert Katz Publications

Electricity is the basis of our present highly technical civilization. It is the means whereby energy from various sources is delivered to the consumer in a form suitable for its conversion into the many kinds of energy demanded by him. It is through the intermediary of the electric circuit that energy is transmitted electrically from the primary source, no matter where it is situated, to the ultimate consumer wherever he desires it. A complete electric circuit contains some form of electric generator, which is essentially a device for converting other forms of energy to electrical energy, a set of conductors …

2. The Theory Of Special Relativity, Robert L. Bloom, Basil L. Crapster, Harold L. Dunkelberger, Charles H. Glatfelter, Richard T. Mara, Norman E. Richardson, W. Richard Schubart

Section XX: Meaning in the Physical Sciences

Albert Einstein (1879-1955) published his first work on relativity in 1905, the same year in which he published remarkable papers on Brownian motion and the photoelectric effect. At the time he did this work, he was a patent examiner in the Swiss Patent Office. He was awarded the Nobel Prize for physics in 1921 "for his services to the theory of physics, and especially for his discovery of the law of the photoelectric effect." He became a professor of physics at several German universities, and in 1916, he took a position at the Kaiser Wilhelm Institute in Berlin.

As the …

Physics, Preface, Henry Semat, Robert Katz

Robert Katz Publications

This book is intended for students of science and engineering; it aims to develop both an understanding of the important concepts of physics and some analytical skill in the solutions of problems. The mathematical level of the book is such that it may be used by students who are taking a course in calculus concurrently.

The notations and methods of the calculus are introduced early in the text, beginning with the concept of a derivative in the discussion of motion, and are then extended to more complex problems as the student progresses both in physics and in mathematics. Vector algebra …

Physics, Contents, Henry Semat, Robert Katz

Robert Katz Publications

Table of contents

Physics, Chapter 1: Fundamental Quantities, Henry Semat, Robert Katz

Robert Katz Publications

Physics is a fundamental science dealing with matter and energy. By convention, the subject matter of physics has been divided into such topics as mechanics, heat, sound, light, and electricity. In addition to these general classifications, present-day physics includes atomic physics, nuclear physics, solid-state physics, chemical physics, biophysics, and many other subdivisions. It is impossible to include all aspects of physics in a single definition or paragraph, and to distinguish physics clearly from its nearest neighbors, the other physical sciences-astronomy., chemistry, and geology.

Physics, Chapter 13: Properties Of Matter, Henry Semat, Robert Katz

Robert Katz Publications

When a system is subjected to external forces, it generally undergoes a change in size or shape or both. We have thus far touched very lightly on such changes; for example, we have considered the change in length of an elastic spring and the change in volume of a gas when such systems were subjected to varying pressures. The changes produced in a system by the action of external forces depend upon the physical properties of the material of which the system is composed. A study of the properties of matter leads to information which is of practical value to …

Physics, Chapter 12: Periodic Motion, Henry Semat, Robert Katz

Robert Katz Publications

One of the more important problems in mechanics is the study of periodic motions, that is, motions which repeat themselves in regular intervals of time, called the period. An example of periodic motion which we hrNe already encountered is uniform circular motion, in which the velocity and acceleration of the body at a given angular position were always the same. If a particle was found at a given position at a time t, we could be sure that it would return to that position at time t + T later, where T was the period of the rotational motion. A …

Physics, Chapter 11: Rotational Motion (The Dynamics Of A Rigid Body), Henry Semat, Robert Katz

Robert Katz Publications

The motion of the flywheel of an engine and of a pulley on its axle are examples of an important type of motion of a rigid body, that of the motion of rotation about a fixed axis. Consider the motion of a uniform disk rotating about a fixed axis passing through its center of gravity C perpendicular to the face of the disk, as shown in Figure 11-1. The motion of this disk may be described in terms of the motions of each of its individual particles, but a better way to describe the motion is in terms of …

Physics, Chapter 10: Momentum And Impulse, Henry Semat, Robert Katz

Robert Katz Publications

An extremely important concept in the development of mechanics is that of momentum. The momentum of a body is defined as the product of its mass by its velocity. We shall use the symbol p to denote the momentum of a body. The momentum of a body is a vector quantity, for it is the product of mass, a scalar, by velocity, a vector. While momentum and kinetic energy are compounded of the same two ingredients, mass and velocity, they are quite different concepts, and one aspect of their difference may be seen in the fact that momentum is …

Physics, Chapter 9: Hydrodynamics (Fluids In Motion), Henry Semat, Robert Katz

Robert Katz Publications

When a liquid flows through a pipe in such a way that it completely fills the pipe, and as much liquid enters one end of the pipe as leaves the other end of the pipe in the same time, then the liquid is said to flow at a steady rate. At any point of the pipe, the flow of the liquid does not change with time. The path of any particle of liquid as it moves through the pipe is called a streamline. We can map the flow of liquid through the pipe by drawing a series of …

Physics, Chapter 4: Statics Of A Rigid Body, Henry Semat, Robert Katz

Robert Katz Publications

In the preceding chapter we observed that a particle would remain in equilibrium, in a state of rest, or in a state of uniform motion in a straight line when the resultant of all the forces acting on it was equal to zero. This condition for equilibrium was extended to larger bodies under either of two possible conditions: If the forces acting on the body were concurrent, that is, if they were directed toward a single point, the body could be treated as if it were a particle; or if the body moved with uniform translational motion in which every …

Physics, Chapter 3: The Equilibrium Of A Particle, Henry Semat, Robert Katz

Robert Katz Publications

A particle which remains at rest or in uniform motion with respect to its frame of reference is said to be in equilibrium in that frame. Centuries ago it was recognized that the state of rest was a natural state of things, for it was observed that objects set in motion on the surface of the earth tended to come to rest. The maintenance of any horizontal motion on earth was thought to require the continued exercise of a force, hence to be a violent motion, while vertical motion like that of a falling body was thought to be natural …

Physics, Chapter 2: Motion Of A Particle (Kinematics), Henry Semat, Robert Katz

Robert Katz Publications

Normally, when we say an object is at rest, we mean that it is at rest with respect to the surface of the earth; when we say a car is moving at a speed of 40 mi/hr, we imply that the motion is taking place at this speed relative to the road. A boat sailing on the river moves with respect to the river's banks, but it also moves with respect to the flowing water in the river. The lift on the wings of an airplane is generated by the motion of the airplane through the air, but it is …

Physics, Chapter 29: The Magnetic Field, Henry Semat, Robert Katz

Robert Katz Publications

Natural magnets, called lodestones, have been known since ancient times. The lodestone, a magnetic oxide of iron called magnetite (Fe₃O₄), was mentioned by Thales of Miletus. By the eleventh century the magnetic compass was known to the Chinese, and in the twelfth century references to the compass were made in Western Europe. The lodestone is capable of attracting pieces of iron and of imparting permanent magnetism to other pieces of iron so that these too could attract iron filings. If an iron bar is magnetized, as the result of being near a piece of lodestone, and …

Physics, Chapter 22: Electrostatics, Henry Semat, Robert Katz

Robert Katz Publications

One simple phenomenon of electricity was known to the ancients: that when a piece of amber was rubbed, it acquired the property of attracting small pieces of paper and other light particles. Records show that Thales of Miletus (circa sixth century B.C.) knew of this property of amber; the Greek word for amber is elektron, hence the name electricity. There was practically no further development of this subject until about the seventeenth century. Otto von Guericke (1602-1686) of Magdeburg built a large sulphur sphere, which, when rotated about an axis and rubbed with his hand, gave off electric sparks. In …

Physics, Chapter 21: Vibrations And Sound, Henry Semat, Robert Katz

Robert Katz Publications

There are two aspects of sound: one is the physical aspect which involves the physics of the production, propagation, reception, and detection of sound; the other, which is the sensation of sound as perceived by the individual, depends upon physiological and psychological effects. It is not desirable to separate the two aspects of sound completely, but the main emphasis in this book must necessarily be on the physical aspect. In this chapter we shall consider mostly musical sounds. A vocabulary has been developed to describe the sensation experienced when a musical sound is heard. Such terms as the pitch of …

Physics, Appendix C, Henry Semat, Robert Katz

Robert Katz Publications

Appendix C: Answers to Odd-Numbered Problems