1. What to do… Open your note packet to page 29.
Answer this question in the “Think About It”
If two people are pushing on a box with the same amount of force, in opposite directions, will the box move?

2. Newton’s First Law Chapter 20 Section 2
SPI: Identify and explain how Newton’s laws of motion relate to the movement of objects.

3. Preview

4. Newton’s 1st Law
An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force.
demo

5. An Object at Rest
Identify an object at rest
Ex: chair on the floor, a plane on a runway
These objects will not start moving until a is exerted on them.
Ex:
push or pull
You tend to fall backward when your school bus starts to move.

6. An Object in Motion
An object moving at a certain velocity will continue to move forever at the same speed and in the same direction unless some unbalanced force acts on it.
Ex: Riding in your car. When the car comes to a stop you would continue to move in the direction of the car, however your seatbelt stops you.

7. Balanced Force
Equal forces in opposite
directions produce no motion

8. Unbalanced Force Unequal opposing forces produce an unbalanced force
causing motion

9. Because there’s almost always an unbalanced force acting upon them.
If objects in motion tend to stay in motion, why don’t moving objects keep moving forever?
Because there’s almost always an unbalanced force acting upon them.
A book sliding across a table slows down and stops because of the force of friction
If you throw a ball upwards it will eventually slow down and fall because of the force of gravity

10. Inertia The tendency of an object to resist a change in its motion
Inertia can be described as the tendency of an object to keep doing whatever it’s doing.

11. Which vehicle has more inertia?
MASS & INERTIA
The more mass an object has, the more inertia the object has.
Therefore an object with a small mass will have a small inertia
Bigger objects are harder to start & stop
Which vehicle has more inertia?

12. Inertia

13. The push of the stopped car.
The truck is in motion. What is the force that causes it to stop?
The car is at rest. What is the force that causes it to move?
The push of the stopped car.
The push of the truck.

14. DO!!
The ball will stay at rest until the boy kicks it with his foot

15. Keys to Understanding At LEAST 5 complete sentences
Summarize the main points of the lesson
Describe in detail the important ideas
Write about concepts you want to remember
This should be helpful to YOU!