Excerpted from

Excerpted from Cracking the AP Physics 1 Exam, 2015 Edition by Steven Leduc, John Miller, and the Staff of The Princeton Review. Copyright © 2014 by TPR Education IP Holdings, LLC. Excerpted by permission of The Princeton Review imprint of the Random House Children's Group, a division of Penguin Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.