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Find the charge on a piece of dust

  1. Aug 28, 2009 #1
    1. The problem statement, all variables and given/known data

    A small piece of dust of mass m = 1.6 g travels horizontally through an electric air cleaner in which the electric field is 511 N/C. The electric force on the particle is equal to the weight of the particle.
    What is the charge on the dust particle?
    If this charge is provided by an excess of electrons, how many electrons does that correspond to?

    2. Relevant equations

    I know i have to solve for q and that my mass is the same as my force..but i have no idea where to even start. any help is appreciated!!

    3. The attempt at a solution
     
  2. jcsd
  3. Aug 28, 2009 #2

    Chi Meson

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    Mass is not force.

    Two forces involved here. Name them and compare their magnitudes (sizes).
     
  4. Aug 28, 2009 #3
    well the reason why i think the mass and force are equal is because it said so in the problem.
     
  5. Aug 28, 2009 #4

    Chi Meson

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    No it did not.

    Read it again. You seem to be making a fundamental error in a specific concept.
     
  6. Aug 28, 2009 #5
    is there any way you can help me set it up? if i can get a beginning equation down i can do the rest of it.
     
  7. Aug 28, 2009 #6

    Chi Meson

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    Look at my first reply and answer the questions I asked.

    I'll repeat, there are two forces involved (mass is still not a force; here on earth, what do you multiply mass with to get a force, and what is that force commonly known as?)
     
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