Unit 4 Lesson 3 Newton’s Laws of Motion Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 Newton’s Laws of Motion Genius at Work How did Sir Isaac Newton contribute to scientific thought? Newton was a English natural philosopher whose work on gravity led him to develop the three laws of motion. Newton’s laws of motion describe the relationships between forces, matter, and motion. These laws were published in the late 1600s in a set of books known as the Principia. Copyright © Houghton Mifflin Harcourt Publishing Company

How did Sir Isaac Newton contribute to scientific thought? Unit 4 Lesson 3 Newton’s Laws of Motion How did Sir Isaac Newton contribute to scientific thought? In the Principia, Newton set forth a scientific method that revolutionized how scientists conducted investigations. In addition to inventing the reflecting telescope, Newton also heavily influenced modern astronomy and mechanical engineering. The impact of his research continues even in modern times. Copyright © Houghton Mifflin Harcourt Publishing Company

To Move or Not to Move What is Newton’s law of inertia? Unit 4 Lesson 3 Newton’s Laws of Motion To Move or Not to Move What is Newton’s law of inertia? Newton was a English natural philosopher whose work on gravity led him to develop the three laws of motion. Inertia is the tendency of an object to resist a change in motion. Unbalanced forces always change the motion of an object because the net force on the object is not zero. Copyright © Houghton Mifflin Harcourt Publishing Company

What is Newton’s law of inertia? Unit 4 Lesson 3 Newton’s Laws of Motion What is Newton’s law of inertia? An object at rest stays at rest when balanced forces cancel each other out for a net force of zero. An object in motion stays in motion until an unbalanced force is applied. Copyright © Houghton Mifflin Harcourt Publishing Company

Why does friction affect motion? Unit 4 Lesson 3 Newton’s Laws of Motion Why does friction affect motion? Friction is a force that opposes motion between objects that are touching. Because of friction, an object rarely maintains constant motion. Friction is an important unbalanced force, since it make everyday actions like walking possible. Copyright © Houghton Mifflin Harcourt Publishing Company

How is the law of inertia applied to everyday situations? Unit 4 Lesson 3 Newton’s Laws of Motion How is the law of inertia applied to everyday situations? Inertia is the property of matter that causes a moving object to keep moving and a stationary object to remain in place. You experience this property when trying to stop on a slippery surface. Automobile safety devices and testing takes the effects of inertia into account. Copyright © Houghton Mifflin Harcourt Publishing Company

Pushing Forward What is Newton’s law of force and acceleration? Unit 4 Lesson 3 Newton’s Laws of Motion Pushing Forward What is Newton’s law of force and acceleration? Newton’s second law of motion states that the acceleration depends on the mass of the object and the net force involved. Acceleration is the rate at which velocity changes over time. Newton developed a way to describe the mathematical relationship among force, mass, and acceleration. Copyright © Houghton Mifflin Harcourt Publishing Company

What is Newton’s law of force and acceleration? Unit 4 Lesson 3 Newton’s Laws of Motion What is Newton’s law of force and acceleration? An object accelerates in the direction of the net force. Acceleration can be calculated using the following equation: F = ma F represents force, m represents mass, and a represents acceleration. Remember that you can rearrange the equation to find the unknown quantity (i.e. a = F/m). Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 Newton’s Laws of Motion How is the law of force and acceleration applied to everyday situations? This law indicates that an object with greater mass requires a greater force to accelerate the object. Engineers use the law of force and acceleration when they design engines for vehicles and construction equipment. Copyright © Houghton Mifflin Harcourt Publishing Company

Action and Reaction What is Newton’s law of action-reaction? Unit 4 Lesson 3 Newton’s Laws of Motion Action and Reaction What is Newton’s law of action-reaction? Newton’s third law of motion states whenever one object applies a force on a second object, the second object applies an equal and opposite force on the first object. The force exerted by the first object is called the action force The force exerted by the second object is called the reaction force. Copyright © Houghton Mifflin Harcourt Publishing Company

What is Newton’s law of action-reaction? Unit 4 Lesson 3 Newton’s Laws of Motion What is Newton’s law of action-reaction? The third law of motion can be restated this way: All forces act in pairs. Action and reaction forces do not act on the same object. The forces are equal but act on different objects and in different directions. Copyright © Houghton Mifflin Harcourt Publishing Company

How is the law of action-reaction applied to everyday situations? Unit 4 Lesson 3 Newton’s Laws of Motion How is the law of action-reaction applied to everyday situations? Gravity is a force of attraction between objects due to their masses. Earth exerts an action force on us and countless objects, but the reaction force is hard to detect because Earth is so massive. Whenever you exert a force on an object, it pushes or pulls on you. Copyright © Houghton Mifflin Harcourt Publishing Company