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Chapter 12 Linear Kinetics of Human Movement Basic Biomechanics, 6th edition By Susan J. Hall, Ph.D. McGraw­Hill/Irwin © 2012 The McGraw­Hill Companies, Inc. All rights reserved. Newton’s Laws What is the law of inertia? A body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state. Basic Biomechanics, 6th edition By Susan J. Hall, Ph.D. 12-2 Newton’s Laws A skater has a tendency to continue gliding with constant speed and direction because of inertia. Basic Biomechanics, 6th edition By Susan J. Hall, Ph.D. 12-3 Newton’s Laws What is the law of acceleration? A force applied to a body causes acceleration of that body • of a magnitude proportional to the force • in the direction of the force • and inversely proportional to the body’s mass F = ma Basic Biomechanics, 6th edition By Susan J. Hall, Ph.D. 12-4 Newton’s Laws What is the law of reaction? • For every action, there is an equal and opposite reaction. • When one body exerts a force on a second, the second body exerts a reaction force that is equal in magnitude and opposite in direction on the first body. Basic Biomechanics, 6th edition By Susan J. Hall, Ph.D. 12-5 ... - tailieumienphi.vn
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