1. Newton’s 1 st Law of Motion a.k.a. The Law of Inertia

2. Main Idea- List on left hand column What is inertia Newton’s 1 st Law Components Force and changing direction Forces in Equilibrium What are balanced forces? What is the support or normal force? What is the SUM of Forces when forces are balanced?

3. Newton’s 1 st Law Video http://www.teachertube.com/viewVideo.ph p?title=Newton_s_First_Law&video_id=10 4323http://www.teachertube.com/viewVideo.ph p?title=Newton_s_First_Law&video_id=10 4323

4. Aristotle was a Greek Philosopher who believed Objects naturally move toward a state of rest. Basically this means… That all rolling objects have a tendency to eventually stop.

5. Two Thousand Years Later Galileo argued that Aristotle was WRONG. He instead said that all objects have the tendency to keep doing what ever they are already doing. This tendency is called INERTIA

6. Inertia In objects at rest causes them to stay at rest. In moving objects causes them to stay moving at a constant speed in a straight line.

7. INERTIA- The tendency for objects to remain the same as they are. The inertia of an object is related to its mass. The greater the mass of an object is, the greater its inertia.

8. Sir Isaac Newton: British Scientist Sir Isaac Newton, described the relationship between motion and force in three laws known as Newton’s laws of motion.

9. Newton’s First Law Components Part 1: An object at rest remains at rest. Part 2: An object in motion remains in motion unless some force is acting on it.

10. Objects At rest Stay at rest unless something else places a FORCE on it. FORCE

11. Objects In Motion Will keep moving with constant velocity unless acted upon by an unbalanced force. FORCE

12. Since Velocity Includes Direction Changing Direction of an objects motion requires force even if the object maintains a constant speed.

13. Newton’s First Law Example A book sliding on carpet comes to rest because friction acts on the book. If no net force acted on the book, the book would continue to move at the same velocity.

14. Equilibrium For Objects at Rest Objects at rest are always being acted upon by forces. So why don’t they start moving? These forces cancel each other out.

15. Balanced Forces Are forces that cancel each other out and do not cause a change in motion for the object.

16. THE SUPPORT FORCE ALSO CALLED THE “NORMAL FORCE” Always pushes perpendicular to surfaces. Keeps objects from falling through those surfaces.

17. When Forces Are Balanced The sum of all force acting on an object are 0 ∑= Sum ∑ of Forces =F1 (Gravity) + F2(Support) = 0

18. Balanced Forces Example A Box sitting on a table is being acted upon by balanced forces. GRAVITY Support Force From Table F2 F1

19. All Forces Are Equal and Opposite So they Are… Balanced, they will not cause a change in state of motion! The box will remain at rest…