1. Physics 106 max.byu.edu website Schedule Reading reports Homework
Clickers
Exams, tutorial lab -see syllabus

2. Discovery of electric charge
700 BC
Greeks Amber (“elektron”) was rubbed with wool
1600 Term “electricity” first used
1700’s Electrical “Fluids”. Benjamin Franklin: one fluid, in excess (“+”) or deficit (“-”)
1900 Electrons are the “fluid” particles in metals (low mass vs protons)
attraction
repulsion

3. Modern view electron -, proton + charge is quantized
e or qe = x10-19 Coulombs

5. Electrostatic charging
by friction
total charge is always conserved
electrons often move to make objects charged

6. Electrostatic charging
by conduction (touching)

7. Electrostatic charging
by induction (for a conductor)
“polarization” of the conductor is the first step

8. Why balloons stick to a wall
both are insulators
polarization of the wall’s surface molecules

9. A cat becomes + charged as it slides down a rubber rod toward a conducting can (A) on an insulated table.
P1. The cat falls lands on can A and runs away. The charge on A is:
a. +
b. –
c. 0
P2. B and C fall separately to the insulated floor. The charge on B is:
P3. The amount of charge on C is:
a. more than on B
b. same as on B
c. less than on B

10. Coulomb’s law for point charges
Charges spread evenly on a sphere act like a point charge

11. Change the lower left charge.
P3. The direction of the total force on the top charge is now closest to
a. right
b. left
c. up
d. down

12. P2. You move a + charge around on the x axis
P2. You move a + charge around on the x axis. In what region can you place the charge so the force on it due to -q, 3q is zero? You don’t need to do math.
a. 1
b. 2
c. 3
+322 -q
+3q 1 2 3 4 5

13. What to do by Thurs Read Ch. 18, some of 19, per schedule
Reading reports 1-3 due Friday
Start on HW 1,2. goal HW 1-3 done by Fri 9pm. Submit by Tues noon.
Register clicker at max.byu.edu
Check calendar, read syllabus