Tuesday, April 29, 2008

Set up ink jet problem on board and allowed students time to work on it. (Also asked for number of excess electrons.)

Went over ink jet problem.

Summarized electric field and potential graphs for oppositely charged parallel plates, charged conducting shell, uniformly charged insulator.

Calculated work by integration of F . dr
E = F/q

V = work/q

Used same math techniques to calculate gravitational PE. Setting GPE at infinity to be zero, calculated the escape velocity from Earth.

Used same equation to calculate size of black hole with mass of Earth.

WebAssign due tonight 10:30PM
Test on Friday on Electrostatics.

Tomorrow we will start with a quiz on the ink jet problem and then go over any questions on the supplemental problem sheet and from WebAssign.