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Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of .108 N when their center-to-center separation is 50 cm. The spheres are then connected by a thin conducting wire. When the wire is disconnected, the spheres repel each other with an electrostatic force of .036 N. Of the initial charges on the spheres, with a positive net charge, what was the (a) negative charge of one of them and (b) the positive charge of the other?

Well I know that I need to use Coulomb's Law since that is all we have studied. I know that I have one equation

[tex]F_{12}=\frac{k|q_1||q_2|}{r^2}[/tex]

[tex]\Rightarrow \frac{k|q_1||q_2|}{.5^2}=.108[/tex]

But I am having a hard time writing the second equation in terms of [itex]q_1[/itex] and [itex]q_2[/itex].

I know that [itex]q_1+q_2[/itex] is a positive number, that should help.

Any hints??

Thanks,

Casey

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# Homework Help: Stupid Charges

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