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Homework Help: Electrostatic Forces on Particles

  1. May 27, 2008 #1
    [SOLVED] Electrostatic Forces on Particles

    "An Astatine 219 nucleus and an alpha particle at a spacing of 1.5 x 10^-15 m are formed during alpha decay. If the initial velocity of the two particles is zero, calculate the ratio of their velocities."

    I was thinking of making a ratio of their kinetic energy, but I'm not sure if that's simplifying the problem too much.

    If I make a ratio, I get:
    .5 x m1 x v1^2 : .5 x m2 x v2^2
    ...

    v1
    --- = sqrt [m2 / m1]
    v2

    Is this right?
     
  2. jcsd
  3. May 27, 2008 #2
    Seems right to me. Conservation of kinetic energy is a handy trick!
     
  4. May 27, 2008 #3
    I'm just not sure if it can be done any other way....because I certainly cannot use force (since force varies with the distance, just like the gravitational potential well). So all I could think of was energy.

    However, I'm particularly unsure because my manipulation basically equates the two kinetic energies; that is, the energy of the alpha particle is the same as that of the astatine particle.
     
  5. May 28, 2008 #4
    Yes, the energies are the same, but the velocities are different.
    This is due to the different masses.
     
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