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Need help with Electric Feilds

  1. Feb 16, 2009 #1
    1. The problem statement, all variables and given/known data
    1. A uniform electric field is directed towards the east with a magnitude of 10 N/C. A proton, moving with a speed of 10^5 m /s, enters the field traveling parallel to it. The proton covers a distance of 4 cm while in the field. Find the proton’s final velocity as it leaves the field.

    2. Relevant equations
    F=(k)(q1)(q2)/r, F=mv^2/r, Ac=v^2/r

    3. The attempt at a solution
    I don't understand how to attempt this problem. Confused about the 4cm, not sure if where to use it. How does the proton's velocity change when it enters an electric field?
  2. jcsd
  3. Feb 16, 2009 #2


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    Homework Helper

    1 newton / coulomb = 1 volts / meter

    And W = q*ΔV

    If you know how far it went in the field (.04 m) * 10 v/m that's how much work was exerted on increasing its kinetic energy isn't it since it was || to its direction of motion?
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