1. Laws of Motion In the 1600’s, Isaac Newton stated three rules explaining how all objects move. These rules have never been proved wrong. They are known as the Three Laws of Motion.

2. Changing Motion What are the only two positions an object can be in? An object can be in motion or at rest. What’s the only way you can change an objects position from being at rest or in motion? You have to put a force into the object.

3. Review: First Law of Motion Objects at rest will stay at rest. Objects in motion will stay in motion, in a straight line at a constant speed.straight line until some force acts on them.

4. First Law of Motion On Earth What force makes objects slow down or stop? What force makes all objects slow down or stop? In space Friction None

5. Inertia The first law of motion is also called the law of inertia.inertia Have you ever tried to push a heavy object like a car? When did you have to use the most force when pushing this object? You should have used the most force when you were trying to get the car to start moving. Once the car started moving you should have used less force. You should have used a lot of force to stop the car.stop the car.

6. What objects have inertia? All objects have inertia. The more mass the object has, the more inertia it has. Very little inertia Much more inertia

7. 1.What’s an object at rest? 2.What can change an objects speed or direction? 3.What objects have inertia? 4.What are two common examples of the First Law? Review: First Law of Motion

8. Second Law of Motion: Page 94 Question: What two factors give an object its force? OBJECTIVE: Students will be able to define and give common examples of the Second Law of Motion. VOCABULARY: Second Law of Motion

9. Write these questions onto page 94 SKIP ONE LINE BETWEEN EACH QUESTION 1.Why would one object have more force than another object? 2.What is the metric unit for force? 3.What is the equation for the second law of motion?

10. Second Law of Motion What would have more force? A toy car moving 2 km/hour or a real car moving the same speed? Why? The real car has more mass?more mass

11. Second Law of Motion What would have more force? A car moving 10 km/hour or the same car moving the 130 km/hour? Why? The fast car has more acceleration.more acceleration

12. Second Law of Motion The amount of force that an object has can be calculated using a simple equation. Remember, force is measured in Newtons (N.). Make sure your answer always has this unit in the answer. Force = mass * acceleration or F = maF = ma

13. Sample problem 1 What is the force of a 4 kg. bowling ball accelerating 3 m/sec 2 ? 4 * 3 = 12 and the unit for force is (N). So the answer is 12 (N). Force = mass * acceleration or F = ma Force = 4 kg. * 3 m/sec 2

14. Sample problem 2 What is the force of a 200 kg. train accelerating 40 m/sec 2 ? 200 * 40 = 8,000 and the unit for force is (N). So the answer is 8,000 (N). Force = mass * acceleration or F = ma Force = 200 kg. * 40 m/sec 2

15. Problem 3: Try this yourself What is the force of a 100 kg. football player accelerating 4 m/sec 2 ? 100 * 4 = 400 and the unit for force is (N). So the answer is 400 (N). Force = mass * acceleration or F = ma Force = 100 kg. * 4 m/sec 2

16. 1.Why would one object have more force than another object? 2.What is the metric unit for force? 3.What is the equation for the second law of motion? Second Law of MotionSecond Law of Motion: Review page 94 Write the answers to these questions into your notes.

17. VOCABULARY Second Law of Motion- the force of an object depends on its mass and its acceleration.