10 - 1 : The Nature of Force

1. 10-1: The Nature of Force How do balanced and unbalanced forces affect an object’s velocity?

2. Anticipatory Set Put a book on your desk. Move the book. Did you push or pull? Can it move without a push or pull?

3. California Standards • Science Standard 8.2.a: Students know a force has both direction and magnitude. • Science Standard 8.2.c: Students know when the forces on an object are balanced, the motion of the object does not change.

4. Input • force: a push or a pull. • newton: the SI unit for the magnitude, or strength of a force. • net force: the combination of all forces acting on an object. • unbalanced forces: will cause the velocity of an object to change. • balanced forces: equal forces acting on one object in opposite directions.

5. Input & Modeling What Is a Force? • A force is described by its magnitude and by the direction in which it acts. • The newton (N) is the SI unit of force. It is named after the English scientist and mathematician Isaac Newton. • You exert about one N of force when you lift a small apple The longer the arrow, the greater the force. Arrows can show direction and strength of a force

6. Input & Modeling Combining Forces

7. Input & Modeling Unbalanced Forces • Unbalanced forces acting on an object result in a net force and cause a change in the object’s velocity. • Unbalanced Forces in the Same Direction: When two forces act in the same direction, the net force is the sum of the two individual forces.

8. Input & Modeling Unbalanced Forces Unbalanced Forces in the Same Direction

9. Input & Modeling Unbalanced Forces • Unbalanced forces acting on an object result in a net force and cause a change in the object’s velocity. • Unbalanced Forces in the Opposite Direction: When two forces act in opposite directions, the net force is the difference between the two individual forces.

10. Input & Modeling Unbalanced Forces Unbalanced Forces in the Opposite Direction

11. Input & Modeling Balanced Forces • Balanced forces acting on an object do not change the object’s velocity. • Balanced Forces in Opposite Directions: When two equal forces act in opposite directions, they cancel each other out.

12. Input & Modeling Balanced Forces Balanced Forces in Opposite Directions

13. iPad Exploration Florida Website: Weekly Standards • Lesson 10-1 Activity (in class on iPads) • 1.  Click on the link and take notes about Force in the "rules" box of your notes.  Force Activity (rules) • 2.  Click on the link and read about Direction and Size of Forces.  Complete the "Activity" on your whiteboard.  Direction of Force Activity • 3.  Click on the link, read, and take notes about Balanced & Unbalanced Forces. Balanced and Unbalanced Forces Activity  Complete the "Activities" at the bottom of the page.  The Calculating net force requires a paper from Mrs. Chase, Balanced or unbalanced? is done on the iPad.  You may complete Balancing man at home for fun if you would like.

14. HOMEWORK CONNECTION • Read pages 374-377 in your Science textbook. • Complete the Section 10-1Review & Reinforce • Write a detailed SUMMARY of the section and complete the UNANSWERED QUESTIONS section of your notes. • Choose two of the remaining Depth & Complexity ICONS in your notes and explain how they relate to this section.