College Physics: A Strategic Approach 4th Edition

Book Preface

In 2006, we published College Physics: A Strategic Approach, a new algebra-based physics textbook for students majoring in the biological and life sciences, architecture, natural resources, and other disciplines. As the first such book built from the ground up on research into how students can more effectively learn physics, it quickly gained widespread critical acclaim from professors and students alike. For this fourth edition, we have continued to build on the research-proven instructional techniques introduced in the first edition while working to make the book more useful for instructors, more relevant to the students who use it, and more connected to the other subjects they study.

Objectives
Our primary goals in writing College Physics: A Strategic Approach are:
■ To provide students with a textbook that’s a more manageable size, less encyclopedic in its coverage, and better designed for learning.
■ To integrate proven techniques from physics education research into the classroom in a way that accommodates a range of teaching and learning styles.
■ To help students develop both quantitative reasoning skills and solid conceptual understanding, with special focus on concepts well documented to cause learning difficulties.
■ To help students develop problem-solving skills and confidence in a systematic manner using explicit and consistent tactics and strategies.
■ To motivate students by integrating real-world examples that are relevant to their majors—especially from biology, sports, medicine, the animal world—and that build upon their everyday experiences.
■ To utilize proven techniques of visual instruction and design from educational research and cognitive psychology that improve student learning and retention and address a range of learner styles.
A more complete explanation of these goals and the rationale behind them can be found in Randy Knight’s paperback book, Five Easy Lessons: Strategies for Successful Physics Teaching. Please request a copy from your local Pearson sales representative if it is of interest to you (ISBN 978-0-805-38702-5).

What’s New to This Edition

In previous editions of the text, we focused on how students learn physics. Each chapter was built from the ground up to present concepts and problem-solving strategies in an engaging and effective manner. In this edition, we are focusing on why students learn physics. This is a question our students often ask. Why should a biology major take physics? A student planning a career in medicine? This book is for a physics course, but it’s a course that will generally be taken by students in other fields.

The central goal of this edition is to make the text more relatable to the students who will use it, to add examples, explanations, and problems that show physics at work in contexts the students will find engaging. We’ve considered extensive feedback from scores of instructors and thousands of students as we worked to enhance and improve the text, figures, and end-of-chapter problems. Instructors need not be specialists in the life sciences or other fields to appreciate the new material. We’ve done the work to connect physics to other disciplines so that instructors can use this material to engage their students while keeping their focus on the basic physics.

Making the text more relatable meant making significant changes throughout the
book. These edits aren’t cosmetic add-ons; they reflect a thorough reworking of each
chapter. Changes include:

■ Guided by an evolving consensus in the Introductory Physics for the Life Sciences community, we have included new sections on the nature of the drag force at different scales, qualitative and quantitative descriptions of diffusion, and other topics of interest to life science students.
■ We have added a great deal of new material that stresses the application of physics to life science topics. For example, we have expanded our treatment of vision and vision correction, included new material on structural color in animals andplants and the electric sense of different animals, and added new sections on the circulatory system and on forces and torques in the body.
■ We have made new connections between physics topics and other courses that students are likely to take. For example, a new section connects the concept of the conservation of energy to topics from chemistry, including ionization energy and the role of catalysts in reactions. We have continued this approach when we introduced the concept of electric potential energy.
■ Hundreds of new end-of-chapter questions and problems show physics at work in realistic, interesting situations. We have replaced problems that are artificial and abstract with problems that use real data from research in life science fields, problems that show the physics behind modern technologies, and problems that use physics to explore everyday phenomena. We have used the wealth of data from MasteringTM Physics to make sure that we have problems of a wide range of difficulties for each topic and problem-solving approach. A rigorous blind-solving and accuracy cross-checking process has been used to check all new problems to be sure that they are clearly worded and correct in all details, that they are accompanied by carefully worked out solutions.
■ New examples throughout the book use the concepts of the chapters to explore realistic situations of interest to the students—from how bees use electric fields to locate promising flowers to how a study of force and torque in the jaw explains why dogs have long snouts and cats don’t.
■ We have changed the photos and captions at the starts of the chapters and parts of the text to better interest and engage students. The questions that are raised at the starts of the chapters aren’t rhetorical; they are questions that will be answered in the flow of the chapter.

We have also made a number of changes to make the text an even more effective tool for students:
■ A new STRATEGIZE step in examples shows students the “big picture” view before we delve into the details. Classroom testing of this addition has shown it to be quite popular with students, and quite effective in teaching problem-solving skills.
■ Key Concept figures encourage students to actively engage with key or complex figures by asking them to reason with a related STOP TO THINK question.
■ Additional STOP TO THINK questions provide students with more crucial practice and concept checks as they go through the chapters. The solutions to these questions have been moved to a more prominent location.
■ We now provide Learning Objectives keyed to relevant end-of-chapter problems to help students check their understanding and guide them in choosing appropriate problems to optimize their study time.
■ Streamlined text and figures tighten and focus the presentation to more closely match student needs. We’ve scrutinized every figure, caption, discussion, and photo in order to enhance their clarity and focus their role.
■ Increased emphasis on critical thinking, modeling, and reasoning, both in worked examples and in end-of-chapter problems, promotes these key skills. These skills are especially important for students who are taking the MCAT exam.

■ Expanded use of realistic and real-world data ensures students can make sense of answers that are grounded in the real world. Our examples and problems use real numbers and real data; they test different types of reasoning using equations, ratios, and graphs.

We have made many small changes to the flow of the text throughout, streamlining derivations and discussions, providing more explanation for complex concepts and situations, and reordering and reorganizing material so that each section and each chapter have a clearer focus. We have updated our treatment of entropy and the second law to better match current thinking. We have reordered the presentation of material on motion in two dimensions to be more logical. Every chapter has significant and meaningful changes, making this course especially relevant for today’s students.

We know that students increasingly rely on sources of information beyond the text, and instructors are looking for quality resources that prepare students for engagement in lecture. The text will always be the central focus, but we have added additional media elements closely tied to the text that will enhance student understanding. In the Technology Update to the Second Edition, we added Class Videos, Video Tutor Solutions, and Video Tutor Demonstrations. In the Third Edition, we added an exciting new supplement, Prelecture Videos, short videos with author Brian Jones that introduce the topics of each chapter with accompanying assessment questions. In the front of this book, you’ll find an illustrated walkthrough of the new media available in this technology update for the third edition:
■ NEW! What the Physics? Videos bring new, relatable content to engage students
with what they are learning and promote curiosity for natural phenomena. These short videos present visually stimulating physical phenomena and pause throughout to address misconceptions and ask conceptual questions about the physics at hand. The videos are embedded in the eText as well as assignable in Mastering Physics. Quantitative questions are also available for assignment.
■ NEW! Direct Measurement Videos are short videos that show real situations of physical phenomena. Grids, rulers, and frame counters appear as overlays, helping students to make precise measurements of quantities such as position and time. Students then apply these quantities along with physics concepts to solve problems and answer questions about the motion of the objects in the video. The problems are assignable in Mastering Physics and can be used to replace or supplement traditional word problems, or as open-ended questions to help develop problem-solving skills.
■ NEW! The Physics Primer relies on videos, hints, and feedback to refresh students’ math skills in the context of physics and prepares them for success in the course. These tutorials can be assigned before the course begins or throughout the course as just-in-time remediation. They ensure students practice and maintain their math skills, while tying together mathematical operations and physics analysis.
■ NEW! Quantitative Prelecture Videos are assignable, interactive videos that complement the Conceptual Prelecture Videos, giving students exposure to concepts before class and helping them learn how problems for those concepts are worked.
■ NEW! Ready-to-Go Teaching Modules provide instructors with easy-to-use tools for teaching the toughest topics in physics. These modules demonstrate how your colleagues effectively use all the resources Pearson has to offer to accompany College Physics: A Strategic Approach, including, but not limited to, Mastering Physics items. Ready-to-Go Teaching Modules were created for and by instructors to provide easy-to-use assignments for before, during, and after class. Assets also include in-class activities and questions in Learning Catalytics™.
■ Dynamic Study Modules (DSMs) help students study on their own by continuously assessing their activity and performance in real time. Students complete a set of questions with a unique answer format that repeats each question until students can answer them all correctly and confidently.
■ Dynamic Figure Videos in each chapter are one-minute videos based on figures from the textbook that depict important, but often challenging, physics principles.
■ Video Tutor Solutions created by co-author Brian Jones are an engaging and helpful walkthrough of worked examples and select end-of chapter (EOC) problems designed to help students solve problems for each main topic. Each chapter has seven Video Tutor Solutions.
■ Prep questions aligned with the MCAT exam are based on the Foundational
Concepts and Content Categories outlined by the Association of American Medical Colleges. These 140 new problems are assignable in Mastering Physics and available for self-study in the Study Area.
■ Video Tutor Demonstrations feature “pause-and-predict” demonstrations of key physics concepts and incorporate assessment with answer-specific feedback

Brief Contents
PART I Force and Motion
Chapter 1 Representing Motion 4
2 Motion in One Dimension 32
3 Vectors and Motion in Two Dimensions 71
4 Forces and Newton’s Laws of Motion 105
5 Applying Newton’s Laws 134
6 Circular Motion, Orbits, and Gravity 175
7 Rotational Motion 205
8 Equilibrium and Elasticity 244
PART II Conservation Laws
Chapter 9 Momentum 278
10 Energy and Work 309
11 Using Energy 354
PART III Properties of Matter
Chapter 12 Thermal Properties of Matter 396
13 Fluids 441
PART IV Oscillations and Waves
Chapter 14 Oscillations 484
15 Traveling Waves and Sound 518
16 Superposition and Standing Waves 549
PART V Optics
Chapter 17 Wave Optics 586
18 Ray Optics 620
19 Optical Instruments 657
PART VI Electricity and Magnetism
Chapter 20 Electric Fields and Forces 696
21 Electric Potential 734
22 Current and Resistance 774
23 Circuits 800
24 Magnetic Fields and Forces 838
25 EM Induction and EM Waves 879
26 AC Electricity 916
PART VII Modern Physics
Chapter 27 Relativity 950
28 Quantum Physics 986
29 Atoms and Molecules 1019
30 Nuclear Physics 1054