1. Balanced & Unbalanced Forces: 9.2

2. 9.1 Review What is a Force? A push or a pull acting on an object
What Are the (2) Main
Types of Forces?
What Factors Affect Gravity?
A push or a pull acting on
an object
Contact & Non-contact
The mass of the objects &
the distance between them

3. : How Do Forces Affect Motion?
9.2 Key Question
: How Do Forces Affect Motion?
In order to answer this correctly, you must know that the sum of the forces acting on an object can be balanced or unbalanced.
Knowing whether the forces are balanced or unbalanced will help you determine the affect of a force.

4. Forces video

5. Net Force
The combination or sum of all the forces acting on an object is called the …

6. The Net Force of a Balanced Force= 0 N,
BALANCED FORCES
Forces acting on the same object that are equal in strength and opposite in direction are …
The Net Force of a Balanced Force= 0 N,

7. The net force of unbalanced forces > 0 N,
Forces acting on the same object that are NOT equal in strength and/or are NOT opposite in direction are …
The net force of unbalanced forces > 0 N,

8. Which of these three arrows below represents the correct amount of net force of the above two force arrows?

9. 26 N
10 N
Net Force
The change in motion of an object is determined by the net force acting on the object. What is the net force for each situation?
0 N

10. NO CHANGE IN THE MOTION OF THE OBJECT
Balanced forces acting on an object will result in…
NO CHANGE IN THE MOTION OF THE OBJECT

11. 30 N to the right
The net force becomes
0 N. It won’t accelerate.
Unbalanced forces

12. 1. START MOVING 2. STOP MOVING 3. SLOW DOWN
Unbalanced forces acting on an object; it will:
1. START MOVING
2. STOP MOVING
3. SLOW DOWN
4. CHANGE DIRECTION

13. Key Question: How Do Forces Affect Motion?
Balanced forces result in
NO CHANGE IN MOTION.
2. Unbalanced forces result in
A CHANGE IN MOTION
(either speed and/or direction of motion).

14. REVIEW start moving 3. Change direction 4. Change speed
What are the 4 things that can happen to an object when unbalanced forces act on the object?
start moving
2. stop moving
3. Change direction
4. Change speed

15. Apply it!!! Student-Quick-Lab or Teacher-Demo-Lab
You (or your teacher) will make a soda can race across the floor chasing a balloon that has been negatively charged by hair. In the process you will learn how opposite charges attract (negative electrons and positive protons) and transfer electrons from one surface to another.

16. You will need to answer the following questions:
What kind of net force results (balanced or unbalanced)?
What kind of force is it?
Materials:
Balloon
Empty Aluminum Soda Can
Your Hair or a piece of wool

17. Student Lab directions
In groups of 4, blow up the balloon and tie it off.
Find a nice flat, hard, smooth surface (your table or the isle)
Set the aluminum soda can on its side. Make sure its sitting still to begin.
Rub the balloon fast and vigorously on your hair (or a piece of wool) 15 seconds or so. Your charging the balloon up with static electricity.
Hold the balloon out in front of the can. Depending on the weather you may need to hold the balloon as close to 1 inch from the can. Humid weather reduces static electricity.
The can will start to move toward the balloon. If you place the can on the opposite side of the can it will roll in the other direction.
Now, with teacher instruction… teams best player will race the other teams best player.

18. ANSWER! What kind of net force is there (balanced or unbalanced)?
What kind of force is it (be specific)?
Electrical unbalanced force
(that
uses electrons & protons to move the can).