Potential difference between charged parallel plates and hanging sphere

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sully677
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A small sphere with mass 2.10 g hangs by a thread between two large parallel vertical plates 5.00 cm apart . The plates are insulating and have uniform surface charge densities + sigma and - sigma . The charge on the sphere is q = 7.70×10−6 C

What potential difference between the plates will cause the thread to assume an angle of 30.0 degrees with the vertical?
 

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Sounds like a homework question...

What have you tried?
 
Trying the potential difference equations, but the angle is messing my calculations up
 
sully677 said:
bump

In the equilibrium position, what are the forces acting on the charged sphere?
 
The electric field, gravity and the tension of the string?

What formula would I need?
 
sully677 said:
The electric field, gravity and the tension of the string?

What formula would I need?
Draw the free body diagram with these forces. Resolve them into x and y components. For equilibrium equate net X-component and net y-component equal to zero.