- For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction (Newton’s third law).
- The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.
- All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared.
- Do Now– Get out your science notebook and add to the Table of Contents- “What Changes Motion? p.83” (Right Side). Head page 83 properly with “What Changes Motion-Investigation-5/16/17.”
- Investigation– What Changes Motion?- Stack several metal washers on top of the cart. Place a heavy book on the table near the cart. Predict what will happen to both the car and the washers if you roll the car into the book. Write your prediction on p.83. Test your prediction. Record your observations on page 83. What happened to the cat when it hit the book? What happened to the washers? What might be the reason for any difference between the motions of the car and the washers? Does changing the mass on the cart affect your observations?
- Key Words/Notes- Newton’s first law of motion and inertia. Write key words and explanation as a flip page to page 83. Add to your Index.