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Homework Help: Static Electricity and Triangles

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

    Three positive particles of charges 9.0[tex]\mu[/tex]C are located at the corners of an equilateral triangle with .15m sides. Calculate the magnitude and direction of the force on each particle.

    2. Relevant equations


    3. The attempt at a solution

    In class we haven't tried any problems like this so, im not sure how I should approach the problem. when I looked in my text book it explains how to solve similar problems if the triangle is a right traingle but i dont know how im suppose to solve it when its not. Could someone please help me work through this step by step?
  2. jcsd
  3. Feb 1, 2009 #2


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    Homework Helper

    Well the first step is certainly to pick one of the charges and use the formula to find the magnitude of the forces on it due to each of the other charges. Then you draw a diagram showing those two forces as arrows. The two forces (arrows) must be added to get a total and direction.

    There are two approaches for adding vectors. One is to find the x and y components of each one, add the x components, add the y components and then the answer is the hypotenuse of the triangle formed by these.

    The other approach is to place the second arrow so its beginning is at the end of the first arrow. Draw a new vector, the total, from beginning to end of this chain of two arrows. Use Law of Sines and Law of Cosines to solve the triangle and find the length of the total vector and its direction.
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