For Sally Walker and Eileen Palsgrove who made my dreams a reality RF Copyright 2012 by Sally M Walker and Roseann Feldmann All rights reserved International copyright secured No part of this book may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the prior written permission of Lerner Publishing Group Inc except for the inclusion of brief quotations in an acknowledged review Lerner Publications Company A division of Lerner Publishing Group Inc 241 First Avenue North Minneapolis MN 55401 USA For reading levels and more information look up this title at www lernerbooks com Library of Congress Cataloging-in-Publication Data Walker Sally M Put wheels and axles to the test by Sally M Walker and Roseann Feldmann II Title p cm Searchlight books How do simple machines work Includes index ISBN 978 0 7613 5326 3 lib bdg alk paper ISBN 978-0-7613-8011-5 EB pdf 1 Wheels Juvenile literature 2 Axles Juvenile literature I Feldmann Roseann TJ181 5 W36 2012 621 8078 dc22 Manufactured in the United States of America 3 BR 1 1 16 2010029108
Contents Chapter 1 Chapter 2 WORK page 4 MACHINES page 8 FRICTION page 10 Chapter 3 Chapter 4 PARTS OF A WHEEL AND AXLE page 18 Chapter 5 GEARS page 32 (cid:45)(cid:70)(cid:66)(cid:83)(cid:79)(cid:3)(cid:46)(cid:80)(cid:83)(cid:70)(cid:3)(cid:66)(cid:67)(cid:80)(cid:86)(cid:85)(cid:3)(cid:52)(cid:74)(cid:78)(cid:81)(cid:77)(cid:70)(cid:3)(cid:46)(cid:66)(cid:68)(cid:73)(cid:74)(cid:79)(cid:70)(cid:84)(cid:3)(cid:215)(cid:3)(cid:20)(cid:26) (cid:40)(cid:77)(cid:80)(cid:84)(cid:84)(cid:66)(cid:83)(cid:90)(cid:3)(cid:215)(cid:3)(cid:20)(cid:25) (cid:42)(cid:79)(cid:69)(cid:70)(cid:89)(cid:3)(cid:215)(cid:3)(cid:21)(cid:17)
Chapter 1 WORK You work every day At home one of your chores may be doing dishes At school you work when you sharpen your pencil You work at snack time And you work when you race in gym Eating and playing are work too Playing soccer is work What does the word work mean to a scientist 4
Work Using Force to Move an Object When scientists use the word work they don’t mean the opposite of play Work is using force to move an object Force is a push or a pull You use force to do chores to play and to eat You do work when you put newspapers into the recycling bin 5
