Recent content by oreosama

  1. O

    Difficult inductance + torque rolling rail problem

    Homework Statement Homework Equations F = I\vec{l} \times \vec{B} \varepsilon = BLv The Attempt at a Solution Every direction i go seems real wrong F = I\vec{l} \times \vec{B} F = \frac{\varepsilon \vec{l} \times \vec{B}}{R} F = \frac{\varepsilon LB}{R} ma =...
  2. O

    How Do You Calculate Equivalent Resistance in a Complex Circuit?

    ive always understood parallel/series as a visual type thing. youre saying 1/R + 1/3R = 4/3R -> 3R/4 ? I Have no idea what this does to the circuit, as in where this combined resistor would be.. relative to the middle one still standing
  3. O

    How Do You Calculate Equivalent Resistance in a Complex Circuit?

    Homework Statement Hi, this was an extra credit problem on a test I had that I think I remember correctly Given R find R equivilent of the circuit Homework Equations Series R1, R2 = R1 + R2 parallel R1, R2 = (1/R1 + 1/R2)^-1The Attempt at a Solution Never encountered a resistor in an...
  4. O

    Understanding RC Circuits and Voltage Distribution

    Ok. thanks for all this btw. Now here's a variation For the switch being open, the capacitors on each side take all the voltage because i->0 after a long time. Va = V and Vb = 0, Vab = V After the switch closes, there is a current path. This gives 2R some voltage, which means vb and va will...
  5. O

    Understanding RC Circuits and Voltage Distribution

    The only thing I can conceptually be confused about is that you keep saying the caps will charge to that voltage source. but since the two right capacitors must add to V they can't... both, uh, be 1/3V. i think i misunderstand what you mean i guess
  6. O

    Understanding RC Circuits and Voltage Distribution

    so when the switch closes and its been a long time the charge in the capacitors balance such that Vb = Va, and since nothing has changed on the left side, Va is the same making vb 1/3V?
  7. O

    Understanding RC Circuits and Voltage Distribution

    right side i know initially the charge on both capicitors are the same since theyre in series q1=q2 and I know total V across is V = \frac{q}{2c} + \frac{q}{c} = \frac{3q}{2c} so q = \frac{2CV}{3} making V on capicitor1 1/3 V, capacitor 2 2/3V Vb wrt ground would be 2/3 V since 1st...
  8. O

    Understanding RC Circuits and Voltage Distribution

    Homework Statement Given V R C for the figure, determine a. The voltage of a with respect to b when the switch is open? b. Which point a or b is at a the higher voltage? c. What is the final voltage of point b with respect to ground when the switch is closed? d. Wow much...
  9. O

    Capacitance in a conducting cylinder

    Oh my... Does this apply to everything I've done so far? Are you just saying "voltage" is the "opposite of the potential difference"?
  10. O

    Capacitance in a conducting cylinder

    The concept of voltage being constant in a capacitor for some reason was lost on me.. that makes sense. this voltage is the same as the given correct? so q = \frac{VL 2 \pi \epsilon_0}{\ln{1/3}} C = \frac{L 2 \pi \epsilon_0}{\ln{1/3}}
  11. O

    Capacitance in a conducting cylinder

    oh, whoops. I meant ln(3R/2R) -> ln(3/2). you're saying use V(2R) as basis for the capacitance? I was kind of confused on how V(2R) contains all the charge we're talking about, but since the voltage I measured is from the surface of both conductor surfaces it should catch it all? I'm trying to...
  12. O

    Capacitance in a conducting cylinder

    Homework Statement A cylindrical capacitor of length L consists of a solid conducting core with a radius R and an outer outer hollow conducting tube with an inner radius 3R. A voltage V_{ab} is applied between the two cylinders. Assume L >> R which means we can neglect edge effects. Given [L...
  13. O

    Equilateral triangle charged rods

    y = \sqrt{\frac{3}{4}} a ln term collapses to ln{\frac{4}{3}} Is this correct? What about part 3? I only know of 1/2mv^2 which I assume was at least greater than potential it would get out.. but I have no m given.
  14. O

    Equilateral triangle charged rods

    Homework Statement Three rods each of uniform charge Q and length a are formed into an equilateral triangle. Given[Q,a,q] determine: 1. The voltage at the center of the triangle. 2. If a charge -q is placed at the center of the triangle determine potential energy. 3. Determine the initial...
  15. O

    Flux across a plane with varying electric field

    Homework Statement I got home from a test, had an extra credit problem semi memorized and am wondering how I was suppose to solve. http://i.imgur.com/cIOdSvk.png A plane with sides L is at x=3 . An electric field E = α y^2 x i + α z^2 y j passes through (where \alpha is a constant). Find the...
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