Charge It Up

Charge It Up

Charge It Up

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Presentation Transcript

1. Charge It Up Session 2 Spring ‘11

2. Calendar • Today – Charge overview and some background on the actual FORCES between charges. • Coulomb’s Law Introduction. • Sunday – Brief WebAssign is due. • Monday – MLK Birthday – No Class • Wednesday – Additional Work on Forces • Friday – First Quiz • NOTE: Always bring the current unit and the next unit to class.

3. Scotch Tape What’s wrong with this picture?? Two the same! Charge Transfer

4. Types of Charge • Positive • Negative • Squiggle

5. The Atom and Charge Electron (-e) Weakly Bound in a METAL Charge is QUANTIZED (e) or (-e) Electron (-e) Strongly Bound in an INSULATOR Proton (e) Always Immobile

6. Van DerGraaf Generator Charge Transfer

7. H OW ? WHY??

8. SEDUCTION?? ATTRACTION ROLL ! +++++++ EMPTY Coke? Pepsi? Beer? - - - - ++++

9. Balloon Anybody? Polarization

10. Effects • Charge Transfer • Charge Induction • Charge Polarization • Magic

11. Is the FORCE with you?? Observation Noted with the tape? The closer the charges are to each other, the bigger the force between them

12. Coulomb’s Law • F is a VECTOR • q is a charge measured in “Coulombs” (more soon) • k is a constant ~9x109 Nm2/C2

13. More on Coulomb • If the two charges have the same sign, the product of the charges is positive and the force is repulsive • If the two charges have opposite signs, the product of the two charges will be negative and the force will be attractive.

14. A small spherical insulator of mass 2.00 x 10-2 kg and charge +0.600 µC is hung by a thin wire of negligible mass. A charge of −0.900 µC is held 0.150 m away from the sphere and directly to the right of it, so the wire makes an angle θ with the vertical. What is the angle? What is the tension? 46.8.296

15. Start the nextunit Unit 02 Coulomb’s Law