1. Notes: Forces

2. Force-
A push or a pull exerted on an object.

3. Forces can affect motion in several ways:
→ start moving
→ move faster
→ move slower
→ stop moving
→ change direction
→ change shape

4. FORCE FACTS:
→ Forces are measured in Newtons (N) with a tool called a spring scale.
→ Forces usually act in pairs
→ Forces act in a particular direction
→ Forces usually cannot be seen, but their effects can

5. Forces and Direction:
More than one force can act on an object at a time.
The forces can push or pull in any direction.
What happens to the object when the forces act depends on two things:
→ How strong the forces are
→ The direction of the forces

6. Net Force:
The overall force on an object when all the individual forces acting on an object are added together.

7. Calculating Net Force:
To find the net force when forces are acting in the same direction, simply add them together.
30 N to
the right
10 N to
the right
30 N + 10 N = 40 N

8. Calculating Net Force:
To find the net force when forces are acting in opposite directions, simply subtract the smaller force from the larger force.
10 N to
the left
30 N to
the right
30 N – 10 N = 20 N to the right
30 N to
the left
10 N to
the right
30 N - 10 N = 20 N to the left

9. Balanced Force:
Equal forces acting on an object in opposite directions.
When a net force is zero, the forces are balanced.
Balanced forces DO NOT cause changes in motion.

10. Unbalanced Force: A nonzero net force that changes an object’s motion.
When a net force is greater than zero, the forces are unbalanced.

11. Friction-
a force that opposes motion between two surfaces that are touching.

12. Work-
the action that results when a force causes an object to move in the direction of the force.

13. Inertia-
the tendency of all objects to resist any change in motion.