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Homework Help: Current Electricity

  1. May 4, 2008 #1
    [SOLVED] Current Electricity

    1. A positively charged particle enters an evacuated region between two parallel plates with an initial horizontal velocity of 29.6 m/s, as shown in the following diagram. The particle has a mass of 35.6 mg and a charge of +8.40 nC.

    A) Will either the force of gravity or the force of air resistance play a role in the motion on this particle? Support your answer.

    I assumed the force of gravity would act downwards on the particle. I'm not sure though. Haha.

    B) Do the necessary force calculations to determine which plate the particle will strike. Begin your solultion with a labelled diagram.
    So I did the diagram, and this is what I've done so far with the calculations:

    Fnet= Fe + Fg
    Fnet= |Fe|, up + |Fg|, down
    Fnet= +|Fe| + -|Fg|
    ma= q|E| - mg
    a = (qE - mg)/m

    I assume all I need to do is plug in values, but, I have a rather stupid question, what does nC mean? Does it just mean I need to change the +8.40 value to 8.40 x 10^-9?

    Do I appear to have the write idea with the calculations?
  2. jcsd
  3. May 4, 2008 #2
    1) Why do you think gravity would effect the particle? Saying "I'm not sure" is ok, but for me to help you I have to know why you think so.

    2) nC is nano-Coulomb, so you are right, just multiply it by 10^-9.

    3) Your math looks correct. :smile:
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