1. Newton’s Third Law Chapter 5

2. Forces & Interactions  Remember: A force is a push or pull.  In a broader sense, a force is not a thing, but an interaction between 2 things.  You can’t push on a wall without it pushing back on you.  An interaction require a pair of forces acting on two objects  Examples Boxer punching the bag vs. tissue paper Bug and Windshield

3. Newton’s Third Law  When one object exerts a force on a second object, the second object exerts a force on the first with an equal and opposite force.  Objects are always exerting forces on each other. Never one way  Called action/reaction pairs.  To determine the action/reaction pair just switch the nouns.

4. The Third Law and Acceleration  Only forces acting on an object cause it to accelerate, not forces from the object on something else.  Action/reaction forces don’t cancel because they act on different objects Cart example Gun example Rocket example

5. Homework  Chapter 4 RQ 2,3,5,6,9,20,21,23,25,26,29,32,33 Exercises 4,6,19,26,33,42,43 Problems 2,4,8,10  Chapter 5 RQ 2,6