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Homework Help: Electric Charge Problem

  1. Feb 25, 2010 #1
    1. The problem statement, all variables and given/known data

    A small sphere with a charge of 2.36 microCulombs is attached to a relaxed horizontal spring whose force constant is 88.6 N/m. The spring extends along the x axis, and the sphere rests on a frictionless surface with its center at the origin. A point charge Q = - 8.55 microCulombs is now moved slowly from infinity to a point x = d > 0 on the x axis. This causes the small sphere to move to the position x = 0.124 m

    2. Relevant equations

    I dont even know where to begin with this problem :(

    3. The attempt at a solution

    I don't really understand the concept or even how to begin to solve this problem.. any explanation of the concept or where to start would be greatly greatly appreciated!
  2. jcsd
  3. Feb 25, 2010 #2


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    Homework Helper
    Gold Member

    Finding the force on that spring would be a reasonable start (what force would cause a displacement of 0.124 m?). Coulomb's law will help you with the rest.
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