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Lecture 1-2. Charge - Continued. What’s Happ’nin?. By now you should have registered on WebAssign and tried the initial assignment. You should be reading the first chapter. You should have read the syllabus (web). - -. -. -. - +. - +. Summary - Rubbings.
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Lecture 1-2 Charge - Continued
What’s Happ’nin? • By now you should have registered on WebAssign and tried the initial assignment. • You should be reading the first chapter. • You should have read the syllabus (web).
- - - - - + - + Summary - Rubbings
Pithy Happenings Charge Transfer by Contact
Magic? Balloon??
How many ways can we transfer charge? Let us count the ways.……………..Willie the Shake • Direct Contact • Separation of bonds (rubbing, etc,) • Conduction • Induction • Magic.
Coulomb’s Law • F is a vector. • magnitude • direction • 1/4pe0=k=8.99 x 109 Nm2/C2 DEFINITION – Unit of Charge is the coulomb
Very Important Concepts in Physics Superposition Symmetry
Let’s Do Some Problems • Strategy • Think about how you will proceed. • What information is given, what is missing? • Develop the equations in an algebraic format. • Solve for an algebraic solution. • Plug in the numbers at the end. • Look at some special cases to check on consistancy. • Think about what you have learned that is worth retaining.
In the figure, a central particle of charge -2q is surrounded by a square array of charged particles, separated by either distance d or d/2 along the perimeter of the square.
In the figure, particle 1 of charge +1.0 µC and particle 2 of charge -4.0 µC, are held at separation L = 11.0 cm on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the coordinates of particle 3? x=[-11] cm y=[0] cm
What is e?? |e|=1.6 x 10-19 Coulombs Exact value in textbook