1. Agenda This Week –Ch. 27-29 –Skip Lab, No Quiz Next Week –Finish 29, No Quiz –Review Following –Exam II on Monday (2 weeks) –April 6 th [Or previous Friday if prefer] Sections –27.1-27.8 –28.1-28.5 –29.1-29.5

2. Magnetism Much like electric Dipole Combination of –North (+) –& South (-) ALWAYS BOTH

3. Magnetism Lines Originate at N Lines End at S –More Common than E Fields –Why? N S

4. Fields & Forces E & B (Magnetic) Fields –Same –Fields create forces –B & E Fields act on charged particles Different? –B fields act on MOVING charges –E fields act in straight lines –B Fields act in perpendicular directions

5. Right Hand Rule Directions for + Charge in B Field Same Idea as Rotational Motion Negative Charge = Opposite Direction “Left Hand” rule for electrons? Be consistent Or.. F = qvBsin(  ), Use R.H.R. for directions

6. Trial 1 B Field Points Right What is the trajectory for this particle? Positive Charge, Constant Velocity to the Right… +

7. Trial 2 B Field Points Into Screen What is the trajectory for this particle? Positive Charge, Constant Velocity Right? Initial: Force points ? … Down XX X X X X X X X XX X X XX X X X XX X X X XX X X X XX X X X X +

8. Trial 2 B Field Points Into Screen What is the trajectory for this particle? Positive Charge, Constant Velocity Right? Curves Around, now Velocity is Down Force Points? Left… XX X X X X X X X XX X X XX X X X XX X X X XX X X X XX X X X X +

9. Trial 2 XX X X X X X X X XX X X XX X X X XX X X X XX X X X XX X X X X + VoVo Velocity, Force & Field Always Perpendicular When Force always points inwards… Circular Motion

10. Trial 3 B Field Points Right What is the trajectory for this particle? Positive Charge, Constant Velocity Up & Right… To Solve, Separate out x & y components, treat separately +

11. Trial 3a Just Like First Part: B Field Points Right What is the trajectory for this particle? Positive Charge, Constant Velocity to the Right… +

12. Trial 3b Just Like 2 nd Part: B Field Points Right Charge will make circle in yz plane +

13. Trial 3 X part: + Charge travels to right Y Part: Circle in yz plane Combined: Helix: Oscillating circle traveling to right Only 3 choices: Circle, Line, Helix +

14. Trial 4 A wire is located in a field with B pointing right. Current in the wire flows upwards Is there a force on the wire, if so which direction?

15. Break HMWK Assistance? Tomorrow –Finish 27 – Mathematical Problems Wed & Fri –Finish 28, Begin 29 Monday& Tues –Finish 29, Problems Wed –Review Fri –Exam