How Much Charge Do Repelling Styrofoam Balls Carry?

[MightyMan11]

Homework Statement

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?

Homework Equations

Coloumb's law

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?

 

[MightyMan11]

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

 

[nlightner]

I would first double check my calculations and make sure all units are consistent. It is also important to consider any assumptions made during the calculations and whether they are valid. Additionally, I would suggest checking for any errors in the experimental setup or data collection.

If the calculations are correct and there are no errors, I would then consider if there are any external factors that could be influencing the results. For example, are there any other objects or materials nearby that could be affecting the electric charge? Are there any external forces acting on the Styrofoam balls?

If all else fails, I would suggest double checking the values used for the constants in Coulomb's law and making sure they are accurate. It may also be helpful to consult with a colleague or supervisor for a second opinion and to troubleshoot any potential issues.