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Here is my question:

Three identical small Styrofoam balls (m = 2.05 g) are suspended from a fixed point by three nonconducting threads, each with a length of 45.5 cm and with negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 28.4 cm. What is the common charge q carried by each ball?

This is what I have done.

I made my diagram 3d and did a FBD for 1 ball (Tension up and at an angle, mg going down, and Fe going to the left) As a result, solving for the Forces in the x-direction I had

Ftcos60 = Fe

and solving in the y direction

Ftsin60 = mg

I divided EFy by EFx to get rid of the tension force and then solved for Fe. I then put that into the coulomb law equation and made both q charges the same so it was q^2 and solved for q. I am not getting the right answer though. I think my assumption of the angles being 60 may be wrong. Can anybody help out?

Thanks

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# Homework Help: Electrostatic Equillibrium Question

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