1. Warm Up
No Warm up on Sub days

2. Goals
Understand and apply the relationship between electric force, charge, and distance.

3. Coulomb's Law
Electrically charged objects can attract or repel other objects.
An attraction or repulsion is an example of force.
The FORCE OF STATIC ELECTRICITY depends on 3 things

4. Coulomb's Law
1) Are the two charged objects both +, -; or do we have on of each. This determines attract or repel.
2) Strength of each charge.
More charge = stronger force
3) Distance
Farther away, force is weaker

5. Coulomb's Law
Putting all of the ideas from the previous slide we find that
Electric force is equal to (k * Q1 * Q2) / d F = (k * Q1 * Q2) / d2
F = force
Q1 & Q2 are the charges on the objects
d = distance between objects
k = 9 * 109 N m2 / C2

6. Questions
1) When two charged objects get closer together does the electric force become stronger or weaker?
2) When two charged objects get two times as close together the strength of the force gets _____ times bigger/smaller

7. Question
If two objects are near each other and one object is given three times more charge, then the strength of the electric force will
Increase or decrease
By how many times will it increase or decrease?

8. Reading
Conceptual Physics (Hewitt) Pg 504 – 507

9. Worksheet

10. Cool Down