1. Let’s do some cutting!!!
GLUE

2. Forces and Motion
FORCE - a push or a pull, in any direction, that may cause a change in an object’s motion.

3. Every object has several forces always acting on them.
Gravity
Air Pressure
Air Pressure
Friction
Friction
Normal

4. When two equal forces act on an object in opposite directions
When two equal forces act on an object in opposite directions. (Net force = 0 N)
Balanced forces are not moving at a constant speed.
10 N
Net force = 0 N

5. Since the applied force is not stronger than the force of friction the object does not move
Gravity
Air Pressure
Air Pressure
Applied Force
Friction
Normal

6. When two forces are unequal in the size and are moving in opposite directions.
They cause a change in motion in one of these areas:
Position
Direction
Speed
Net force = 10 N (moves to the left)
10 N
20 N

7. If the applied force is strong enough to over come the existing forces, the object will move
Gravity
Air Pressure
Air Pressure
Friction
Applied Force
Normal

8. The sum of all the forces acting on an object.
Expressed in Newtons (N)
10 N
30 N
Net force = 20 N

9. Common Forces
Friction
Magnetic
Gravity
Electricity

10. Friction The force exerted when two objects rub up against each other.
Friction opposes motion. It causes objects to slow down.

11. So why are we not being pulled together right now?
Gravity
The force that pulls objects towards each other
Every object has gravity, meaning that all objects are being pulled toward each other.
So why are we not being pulled together right now?

12. The larger the object is, the more we are affected by its gravitational pull.
We are more attracted to the Earth’s gravity than we are to gravity of the things in the room.

13. Where will the red ball move?
Since the green ball is bigger, its gravity affects the red ball more than the white ball does, so the red ball moves towards the green ball.

14. Why do two different objects not hit the ground at the same time?
Gravity is acting more on the elephant than on the feather. A heavier object overcomes the upward force of air resistance (friction) more easily thus falling faster than the light object.

15. What happens if we can eliminate the air resistance?

16. The two objects hit the ground at the same time
Gravity is still acting more on the elephant than the feather, but the inertia of the elephant keeps it from accelerating faster.
All objects will accelerate the same when the force of gravity is the only force acting on it.

17. Let’s Practice!
The box will move to the left with a net force of 3 N, which indicates that the speed of the box is increasing.

18. The forces are unbalanced, and Horse 2 is pulling with a greater force.

19. Move to the left with a net force of 70 N.