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Homework Help: Resistor and power output varying with a distance x

  1. May 2, 2013 #1
    1. The problem statement, all variables and given/known data
    Figure 29 shows a battery connected across a uniform resistor R0. A sliding contact can move across the resistor from x=0 at the left to x=10 cm at the right. Find an expression for the power dissipated in the resistor R as a function of x. Plot the function for ℰ=50 V, R=2000Ω , and R0=100Ω

    2. Relevant equations

    3. The attempt at a solution
    I have no clue at all on how to solve this problem. I think that it might have to do with how resistors are adding up in parallel. I really can't see which one is in parallel. I don't see how to determine the resistance with the varying x.

  2. jcsd
  3. May 2, 2013 #2
    This circuit is equivalent to three resistors: Rl, Rr, and R. Rl and Rr are the left and right, correspondingly, parts of Ro; their values depend on x. Solve for voltage at R and current through it.
  4. May 2, 2013 #3


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    It's helpful to post a full size image if it's not too large.

  5. May 2, 2013 #4
    may be this be help..
    [itex] R_{total}=(R // R_{p}) + R_{s})[/itex]


    just as Voko said #2
  6. May 13, 2013 #5

    please explain more about the problem
    Last edited by a moderator: May 6, 2017
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