1. 11.1 Newton’s First Law

2. INERTIA An object at rest remains at rest, and an object in motion maintains its velocity unless it experiences an unbalanced force

3. Stationary objects don’t want to move

4. Moving objects don’t want to stop

5. Mass is a measurement of inertia More mass = more inertia Therefore mass which is a measure of the amount of matter in an object is also a measure of the inertia of an object

6. When you are in a car that is accelerating, you feel like you are being pushed back. When the car comes to a sudden stop, your body wants to continue in a forward motion. Your body’s inertia is resisting the change in speed.

7. When stopping, the coffee tends to spill forward When accelerating, the coffee tends to spill on you.

8. Sudden Stops - seat belts help your body resist the tendency to keep moving. Sudden Starts - head rests stop the head from being pushed back.

9. What will happen without seatbelt?

10. Misconception!! - If no force acts on a moving object, it will eventually come to rest. - Motion requires the presence on a force. Truth!! - Only a force can cause a change in the motion of a moving object. - An object moves at a constant velocity or not at all if there is no force acting on it. What happens when you stop applying a force to an object?