1. How is a fuse different than a circuit breaker?
2. Why does your hair stand on end after being rubbed with a balloon?

2. Q: What’s a Coulomb?
A coulomb is a unit to measure the amount of electrical charge in an object
1 Coulomb = ×1018 electrons
Coulomb's Law is one of
the basic ideas of electricity
in physics.

3. Q: What’s a Coulomb? Tells us 2 things:
As distance increases, the force between objects decrease.
As charges of two objects increase, the force between them increases.

4. Q: What’s a Coulomb?
The force between the objects can be positive or negative depending on whether the objects are attracted (+ force) to each other or repulsed (- force).

5. Q: What’s a Coulomb? Equation to represent Coulombs Law:
It looks scary, but think of Newton’s law of gravitation –
F = G m1m2 / d2
F = k
q1x q2 r2

6. Coulomb’s Law
F = k
q1x q2 r2
F = force
k = constant (changes based on the medium of electron travel)
q = charge of objects (1 and 2)
r = distance between their centers

7. If I quadruple the distance between 2 objects, the electrical force between them will ________ by ____.
If I triple the charges of both objects, the electrical force between them will _______ by _____.
If I triple the charge of one object only, the electrical force between them will _________ by ____.
decrease 16
increase 9
increase 3

8. If I cut the charge of both objects in half, the force between them will _________ by ____.
If I decrease the distance between them by a factor of 5, the force between them will _________ by ____.
decrease 4
increase 25