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Homework Help: Electric Potential conducting shell

  1. Mar 26, 2007 #1
    1. The problem statement, all variables and given/known data
    A thin, spherical, conducting shell of radius R is mounted on an isolating support and charged to a potential of [tex]-V[/tex]. An electron is then fired from point [tex]P[/tex] at a distance [tex]r[/tex] from the center of the shell. [tex](r>>R)[/tex] with an initial speed [tex]v_0[/tex] and directly towards the shell's center. What value of [tex]v_0[/tex] is needed for the electron to just reach the shell before reversing direction?

    2. Relevant equations
    [tex]\Delta u = \frac{1}{2}mv_0^2[/tex]

    3. The attempt at a solution

    [tex]v_0=\sqrt{\frac{2 \Delta u}{m}}[/tex]

    Im not sure if this is what I should do, if so, how can I get something for [tex]\Delta u[/tex]
  2. jcsd
  3. Mar 26, 2007 #2


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    What is the PHYSICS underlying the "relevant equation"?
    What does [tex]\Delta u[/tex] mean? and how is it related to the "Electric Potential"?
  4. Mar 26, 2007 #3
    Conservation of Energy Kinetic Energy + Potential Energy = Constant.
    Delta U = changes in Potential Energy
    = e*V


  5. Mar 26, 2007 #4
    does "V" have a value?
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