Parallel plates capacitance

[AgPIper]

A parallel plate capacitor has charge Q and plates of area A. What force acts on one plate to attract it toward the other plate?

It's F = Q^2 / (2*8.854e-12*A) ... something to do with the electric field divided in 2? Wondering why there's a 2 in the denominator... thanks :)

[Doc Al]

To find the force that one plate exerts on the other, first find the field created by the charge on that plate. That's where the 2 will come in.