(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

9. Two identical conducting spheres, fixed in place attract each other with an electrostatic forces of 0.108 N when their center-to-center separation is 50.0 cm. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other with an electrostatic forces of 0.0360 N. Of the initial charges on the spheres, with a positive net charge, what was

(a) the negative charge on one of the, and

(b) the positive charge on the other?

2. Relevant equations

[tex]

\vec{F}_{12} = \frac{kq_{1}q_{2}}{r^2}\hat{r_{21}}

[/tex]

3. The attempt at a solution

I know I can use Coulomb's law to solve this problem, however I want to just make sure I first understand the vector form of it.

So, the law

[tex]

\vec{F}_{12} = \frac{kq_{1}q_{2}}{r^2}\hat{r_{21}}

[/tex]

basically says that q1 and q2 are treated as positive where the: negative sign for attraction or positive sign for repulsion; comes from the radial hat vector right?

Ok, so for example in this problem, we have two charges q1 and q2:

http://img162.imageshack.us/img162/1843/91rg6.png [Broken]

Ok, so using the vector form of coulomb's law I treat q1 and q2 as positive charges and the negative sign for attraction should come from the radial vector....but how?

And since this is a radial vector the direction of [itex]\hat{r_{21}}[/itex] is that: the distance beginning at q2 to q1 or beginning at q1 to q2?

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# Homework Help: Two Conducting Spheres Problem - Applying

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