1. Balanced and Unbalanced Forces
Essential Question: How do forces effect motion?

2. Force Any push or pull on an object Act in pairs
Measured in Newtons (N)
Force = mass x acceleration
Every force has a magnitude (size) and a direction
Forces can work together or against each other
Forces can be balanced or unbalanced

3. Balanced Forces Occurs when there is NO CHANGE in an objects motion
No acceleration – no change in motion
objects are at rest or traveling at a constant speed and direction (constant velocity)

4. Balanced forces
No Acceleration = no change in motion, all forces acting on the object are equal and opposite of each other meaning the Net Force is 0.

5. Unbalanced Forces
Always cause a change in motion which is called acceleration
Acceleration – change in speed and/or direction of an object
Starting
Stopping
Speeding up
Slowing down
Turning

6. Net Force
Combination of all forces acting on an object.
Can be balanced or unbalanced

7. Add forces working in the same direction.
Calculating Net Force
Add forces working in the same direction.

8. Subtract forces that are working in opposite directions.
Calculating Net Force
Subtract forces that are working in opposite directions.

9. Vectors Lines with arrows that show force.
Length of the line shows the amount of force (magnitude)
The longer the vector, the greater the magnitude.
The arrow shows the direction of the force.

10. Some Forces Act Through Direct Contact
Applied forces involve direct contact with an object
Friction – a force that opposes the motion between two surfaces that are in contact

11. Some Forces Act at a Distance
Gravity – the universal attraction that exists between all objects. This pull gives the object its weight.
Weight – a measure of the force of gravity acting on an object.
Magnetism – another noncontact force. Magnets attract materials that contain iron.

12. Add forces acting in the same direction
Net Force: 14 Newtons (8+6=14)
Direction of Force: Right

13. Subtract forces acting in opposite directions
Net Force: 2 Newtons (20-18=2)
Direction of Force: Left

14. Net Force = 0 Forces are balanced
Net Force = 0 Newtons (20-20=0)
Forces are balanced - No change in motion

15. Net force and direction
What is the net force?
What is the direction of the force?
Why?

16. Net force and direction
What is the net force?
20 N
What is the direction of the force?
Left
Why?
The team on the left is pulling with more force.

17. Determine the Net Force and Motion of the balloon below