1. SCIENCE 6

2. Review How do we know when an object is in motion?
When its distance from another object is changing

3. Review
What do we use to measure motion?
Speed
Velocity
Acceleration

4. Forces
Study Pack #6

5. Today’s Goals… I can describe how forces affect motion.
I can explain the difference between balanced and unbalanced forces.

6. What is a force? A force is a push or a pull
When one object pushes or pulls another object you can say that the first object is exerting a force on the second object!
For example:
You exerted a force on the books when you made them move
You exert a force on your pencil when you write
You exert a force on a rock when you throw it

7. What is a force?
Forces can be described by how strong they are AND in what direction
When you pushed the book you exerted a force in a different direction than when you pulled the book!
Some of the forces you exerted on the books may have been stronger than others!

8. What is a force? Forces are measured with a spring scale
The units for forces are newtons (N)

9. Unbalanced Forces
Imagine that you need to push a heavy desk across the floor
When you push on the desk you are exerting a force
If a friend helps you, then the total force exerted on the desk is your force plus your friend’s force!

10. Unbalanced Forces
When two forces act in the same direction you add them together =

11. Unbalanced Forces
When two forces act in opposite directions they combine by subtraction
If one force is greater than the other, then the overall force is in the direction of the greater force =

12. Unbalanced Forces The overall force is sometimes called the net force
When there is a net force acting on an object, then the forces are said to be unbalanced
Unbalanced forces acting on an object will change an object’s motion

13. Balanced Forces
Forces exerted on an object do not always change an object’s motion or cause it to move
balanced forces are equal forces acting on an object in opposite directions

14. Balanced Forces One force is exactly balanced by the other
Balanced forces acting on an object will not change the object’s motion
When you add equal forces exerted in opposite directions the net force = =

15. Revisiting today’s goals…
I can describe how forces affect motion.
I can explain the difference between balanced and unbalanced forces.

16. Assignment!
Exit Slip