Help with a physics problem!

[imaqtpie]

Here is the questions - puu.sh/2P5ST.png

Any kind of help is appreciated. Equations if needed,

Potentional Energy:  EP= KQq/r

Electric potentional: V= KQ/r

Electric Potential difference: (delta)V= (delta)Ep/q

Potential Energy into kinectic: (delta) Ek=q(delta)V -----> (1/2)mv^2= q(delta)V.

I'm not sure where i can use the Mass. Any help on answering this question is highly appreciated. This is probably very easy for some of the people in here.

[Wirespeed]

It's been way too long since I've dealt with E&M, but let me see if I can't come up with something.

I can see that it says the charge is "Suspended" between the two plates despite the fact that it *is* positively charged and should be being forced towards the negatively charged plate - this is where mass comes in: the force of gravity, pointing down, must be enough to offset the electromagnetic attraction/repulsion.

Try drawing the free body diagram of the particle and then refer to statics (i.e. \(\sum F = 0\)). You should be able to figure out the electrostatic force resulting from the plates from there and use that to figure out the potential difference if I remember my formulas correctly. I'll doublecheck that real quick

Anyway, I suppose if you could figure out the electric potential energy from there, then it should be trivial to calculate the potential difference. If I recall correctly, \(U_E = q V\)

I might be way off though.