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

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

Modern view electron -, proton + charge is quantized e or qe = 1.602x10-19 Coulombs

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

Electrostatic charging by conduction (touching)

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

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

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

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

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

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 1 2 3

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