# [SOLVED] Explaining an equation

#### Legato

In the figure, two tiny conducting balls of identical mass m and identical charge q hang from nonconducting threads of length L. Assume that θ is so small that tan(θ) can be replaced by its approximate equal, sin(θ).

(a) Show that equilibrium separation x of the balls is given by the equation below.

I know to use Coulomb's Law [ q1*q2/(4*pi*epsilon*r^2) ] but I'm unable to prove the given equation from that. I can't get passed the effects of changing theta as q and/or m change. Can someone give me a step-by-step explanation on this? Thank you.

#### clombard1973

In the figure, two tiny conducting balls of identical mass m and identical charge q hang from nonconducting threads of length L. Assume that θ is so small that tan(θ) can be replaced by its approximate equal, sin(θ).

(a) Show that equilibrium separation x of the balls is given by the equation below.

I know to use Coulomb's Law [ q1*q2/(4*pi*epsilon*r^2) ] but I'm unable to prove the given equation from that. I can't get passed the effects of changing theta as q and/or m change. Can someone give me a step-by-step explanation on this? Thank you.
Hi there,
I've attached a pdf file that shows the complete derivation for the proof of the final equation that you needed to be proved true. I hope it helps.
Many Smiles,
Craig (Hi)

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