Essential University Physics (3rd Edition)

Book Preface

Welcome to physics! Maybe you’re taking introductory physics because you’re majoring in a field of science or engineering that requires a semester or two of physics. Maybe you’re premed, and you know that medical schools are increasingly interested in seeing calculus-based physics on your transcript. Perhaps you’re really gung-ho and plan to major in physics. Or maybe you want to study physics further as a minor associated with related fields like math or chemistry or to complement a discipline like economics, environmental studies, or even music. Perhaps you had a great high-school physics course, and you’re eager to continue. Maybe high-school physics was an academic disaster for you, and you’re approaching this course with trepidation. Or perhaps this is your first experience with physics. Whatever your reason for taking introductory physics, welcome!

And whatever your reason, my goals for you are similar: I’d like to help you develop an understanding and appreciation
of the physical universe at a deep and fundamental level; I’d like you to become aware of the broad range of natural and technological phenomena that physics can explain; and I’d like to help you strengthen your analytic and quantitative problemsolving skills. Even if you’re studying physics only because it’s a requirement, I want to help you engage the subject and come away with an appreciation for this fundamental science and its wide applicability. One of my greatest joys as a physics teacher is having students tell me after the course that they had taken it only because it was required, but found they really enjoyed their exposure to the ideas of physics.

Physics is fundamental. To understand physics is to understand how the world works, both in everyday life and on scales of time and space so small and so large as to defy intuition. For that reason I hope you’ll find physics fascinating. But you’ll also find it challenging. Learning physics will challenge you with the need for precise thinking and language; with subtle need for skillful application of mathematics. But there’s also a simplicity to physics, a simplicity that results because there are in physics only a very few really basic principles to learn. Those succinct principles encompass a universe of natural phenomena and technological applications.

I’ve been teaching introductory physics for decades, and this book distills everything my students have taught me about the many different ways to approach physics; about the subtle misconceptions students often bring to physics; about the ideas and types of problems that present the greatest challenges; and about ways to make physics engaging, exciting, and relevant to your life and interests.

I have some specific advice for you that grows out of my long experience teaching introductory physics. Keeping this advice in mind will make physics easier (but not necessarily easy!), more interesting, and, I hope, more fun:
● Read each chapter thoroughly and carefully before you attempt to work any problem assignments. I’ve written this text with an informal, conversational style to make it engaging. It’s not a reference work to be left alone until you need some specific piece of information; rather, it’s an unfolding “story” of physics—its big ideas and their applications in quantitative problem solving. You may think physics is hard because it’s mathematical, but in my long experience I’ve found that failure to read thoroughly is the biggest single reason for difficulties in introductory physics.
● Look for the big ideas. Physics isn’t a hodgepodge of different phenomena, laws, and equations to memorize. Rather, it’s a few big ideas from which flow myriad applications, examples, and special cases. In particular, don’t think of physics as a jumble of equations that you choose among when solving a problem. Rather, identify those few big ideas and the equations that represent them, and try to see how seemingly distinct examples and special cases relate to the big ideas.
● When working problems, re-read the appropriate sections of the text, paying particular attention to the worked examples. Follow the IDEA strategy described in Chapter 1 and used in every subsequent worked example. Don’t skimp on the final Assess step. Always ask: Does this answer make sense? How can I understand my answer in relation to the big principles of physics? How was this problem like others I’ve worked, or like examples in the text?
● Don’t confuse physics with math. Mathematics is a tool, not an end in itself. Equations in physics aren’t abstract math, but statements about the physical world. Be sure you understand each equation for what it says about physics, not just as an equality between mathematical terms.
● Work with others. Getting together informally in a room with a blackboard is a great way to explore physics, to clarify your ideas and help others clarify theirs, and to learn from your peers. I urge you to discuss physics problems together with your classmates, to contemplate together the “For Thought and Discussion” questions at the end of each chapter, and to engage one another in lively dialog as you grow your understanding of physics, the fundamental science.