PREFACE This Student Solutions Manual and Study Guide has been written to accompany the textbook Physics for Scientists and Engineers, Eighth Edition, by Raymond A. Printed in the United States of America 1 2 3 4 5 6 7 8 9 10 13 12 11 10 09 Purchase any of our products at your local college store or at our preferred online store For permission to use material from this text or product, submit all requests online at Further permissions questions can be emailed to For your course and learning solutions, visit For product information and technology assistance, contact us at Cengage Learning Customer & Sales Support, 1-80 ISBN-13: 9781439048542 ISBN-10: 1-4390-4854-1 Brooks/Cole 20 Channel Center Street Boston, MA 02210 USAĬengage Learning products are represented in Canada by Nelson Education, Ltd. No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution, information networks, or information storage and retrieval systems, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the publisher. © 2010 Brooks/Cole, Cengage Learning ALL RIGHTS RESERVED. May not be copied, scanned, or duplicated, in whole or in part. Serway Emeritus, James Madison UniversityĬopyright 2010 Cengage Learning, Inc. Gordon Emeritus, James Madison University The importance of the work-energy theorem, and the further generalizations to which it leads, is that it makes some types of calculations much simpler to accomplish than they would be by trying to solve Newton’s second law.Student Solutions Manual and Study Guide for S ERWAY If you leave out any forces that act on an object, or if you include any forces that don’t act on it, you will get a wrong result. When calculating the net work, you must include all the forces that act on an object. If an object speeds up, the net work done on it is positive. (credit: “Jassen”/ Flickr)Īccording to this theorem, when an object slows down, its final kinetic energy is less than its initial kinetic energy, the change in its kinetic energy is negative, and so is the net work done on it. The work done by the horses pulling on the load results in a change in kinetic energy of the load, ultimately going faster. Let’s start by looking at the net work done on a particle as it moves over an infinitesimal displacement, which is the dot product of the net force and the displacement:įor the mathematical functions describing the motion of a physical particle, we can rearrange the differentials dt, etc., as algebraic quantities in this expression, that is,įigure 7.11 Horse pulls are common events at state fairs. Therefore, we should consider the work done by all the forces acting on a particle, or the net work, to see what effect it has on the particle’s motion.
We have discussed how to find the work done on a particle by the forces that act on it, but how is that work manifested in the motion of the particle? According to Newton’s second law of motion, the sum of all the forces acting on a particle, or the net force, determines the rate of change in the momentum of the particle, or its motion. Use the work-energy theorem to find information about the forces acting on a particle, given information about its motion.Apply the work-energy theorem to find information about the motion of a particle, given the forces acting on it.By the end of this section, you will be able to: