A Note to the Instructor about the Second Edition

Algebra-based physics courses always present a serious problem for the instructor. Physicists live and die by calculus and vectors. They provide the structure which physics needs to be a logically organized body of knowledge. In constructing an algebra-based course, we deny ourselves the use of derivatives and integrals, and typically we greatly restrict our use of vectors. What is left is usually an encyclopedic collection of facts more or less unrelated except by accidental sequence.

The first edition of this book was intended to address this problem. The typical student of such a course is pursuing a career in a health-related discipline and is taking the course only because it is a requirement for entry into their particular program. The application of typical first-year physics topics to problems in biology and chemistry provides a unifying theme which appears to have been at least moderately successful as measured by both motivation and retention of students. This focus has the additional benefit of providing a rationale for the choice of material to be included in the text. A few topics, such as gravitation and alternating current, can be omitted for lack of relevance to biological systems, or because a relevant treatment would require calculus. Other topics which are usually omitted in practice, such as fluids, become necessary for a reasonably complete treatment.

But the use of a text in a class of live students is often very different from its apparent usefulness during the preparation of a syllabus. For a student to be successful in a physics class, by the standards of the instructor, he or she must not only become competent in solving problems, but must also understand and use the physical principles involved during their solution. Our students most often bring to their study of physics a very low level of mathematical sophistication, but an average to above-average ability with the mechanical aspects of algebra. At the end of the year you have a class of reasonably bright people who can get the right answers to most of your problems, and who understand very little more physics than when they started.

Many of the problems in the first edition are decent problems from the instructors point of view, but require more complex thought processes than today's students are ready to bring to bear. The Java problem generating programs were written to address this issue, as well as to provide an essentially unlimited supply of practice problems with immediate feedback. For the latter purpose they were wildly successful, and provided several unlooked-for but immediately exploitable benefits. When used as a built-in test bank, they clearly place responsibility for success in the students' hands: the students are tested with problems identical to those they have practiced with, so the only limits to their success are the ones they place upon themselves in terms of discipline and time commitment. The result has been students who come to class more prepared with questions, and who have increased confidence as well as competence at test time.

In the former purpose they were less successful. Each program provides problems which deal with the same physical system and whose solution requires the same set of equations. One of the main differences between students and professors is that students see such a set of problems as an arbitrary grouping of unrelated work, while the professor understands that they are all essentially the same problem. The Java programs were intended to help students see the relationships which are obvious to the professor. In the end they served only to provide a plethora of possibilities for the students to hone their mechanical algebra skills.

This edition began with the re-writing of the Java programs. Whereas the old programs asked random questions about a given system, the new ones attempt to ask a series of questions which follow the course of a more or less complete analysis of the behavior of the system. The new programs also try to encourage the students to develop and use some of the skills and thought processes of the practicing physicist:

Several of the programs were also rewritten to ask harder questions; the more limited range of questions asked by their predecessors encouraged memorization rather than active reasoning as a problem solving strategy. It quickly became obvious that the new programs were going to require changes in the text in order to accommodate the different and extended expectations of student problem solving. And so this new edition was born.

It is actually not so much a new edition as an extended rewrite. The use of voice recognition software has improved the quality and flow of the text, as has the partial reorganization of material. This edition

Many of these changes are tied very closely to our teaching style. As a result, it is uncertain whether this new addition will be as useful in general as its predecessor. If you find it useful, or have any questions or comments about it, we would be happy to hear from you.

About the Third Edition

After teaching with the second edition for a few years, I found that I often referred back to several of the topics omitted from the first edition, either as a result of student questions, or because I wanted to expand a bit on what the students had read. At some point I decided to essentially abandon the first edition, and so combed it relatively thoroughly for crumbs to add to the second as supplemental material. And then my university decided to move from 10-week quarters, and join the rest of the academic world of semesters.

This necessitated a rearrangement of material. It was decided that thermodynamics fit well after mechanics, and the two would make up the first semester. The second would then encompass electricity and magnetism and waves. And in a further fit of conformation, we decided to rename our courses: College Physics would now be the calculus-based version, and General Physics the algebra-based course. These changes constitute, I think, sufficient motivation to label this a "third edition." We hope you find it at least as useful as its predecessors.

The next section is a brief introduction to physics for the student.

©2012, Kenneth R. Koehler. All Rights Reserved. This document may be freely reproduced provided that this copyright notice is included.

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