# 3 Styrafoam Balls Repelling

1. Feb 5, 2009

### MightyMan11

1. The problem statement, all variables and given/known data
Three identical small Styrofoam balls (m = 1.84 g) are suspended from a fixed point by three nonconducting threads, each with a length of 46.5 cm and with negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 30.0 cm. What is the common charge q carried by each ball?

2. Relevant equations
Coloumb's law

3. The attempt at a solution
I've figured out that the repulsive electric force acting on one ball is 6.138e-3 N.
This was done by figuring out the x-component of tension by using the weight.
After that, using coloumb's law, i got that
F = (9.99e10)(q2)
i then figured that the net force would equal F + F.
I added the two force vectors using the cosine law and splitting it into components and i arrive at
q = 1.88e-7 C
however, this seems to be wrong.

Can anyone help please?

Last edited: Feb 5, 2009
2. Feb 5, 2009

### MightyMan11

I solved it!
Could a moderator please close this thread?
Thanks.

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