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Where am I going wrong with this problem?

  1. Feb 9, 2007 #1
    The four 1.0 g spheres shown in the figure are released simultaneously and allowed to move away from each other.


    Here's my attempt at a solution. All sphere's have same charge and are situated in a square.

    [​IMG]

    Thanks.
     
  2. jcsd
  3. Feb 9, 2007 #2

    berkeman

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    Staff: Mentor

    I'm assuming you are asked for the final velocity of each of the masses with respect to the stationary frame of reference. One error I see, 1g does not equal 0.0001kg. The rest of your approach looks reasonable.
     
  4. Feb 9, 2007 #3
    Thanks, corrected the mass (silly me) and recalculated. Computer still doesn't like this answer???

    [​IMG]

    Any ideas?
     
  5. Feb 9, 2007 #4

    berkeman

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    Staff: Mentor

    I'm getting a different exponent on the potential energy terms. Maybe check your units in each of the equations to be sure you are using mks throughout. (Of course I may be calculating the potential energies wrong as well.)
     
  6. Feb 10, 2007 #5
    My goodness it is questions like these that make me so angry. Just got an email back from my Prof he said I need to think about all the pairs in the problem. So I needed to take into account all six pairs in the problem (1 on 2, 1 on 3, 1 on 4, 2 on 3, 2 on 4, and 3 on 4).

    Got the answer correct now thanks for all your help.
     
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