Finding charges on an equilibrium position

[-EquinoX-]

Homework Statement

http://img214.imageshack.us/img214/4430/fieldoc3.th.jpg

E = (3.00i+5.00j) x 10^5 N/C the ball is at equilibrium at 37 degrees, the ball has a mass of 1 gram. What is the charge of the ball? What is the tension of the string?

Homework Equations

E = Fe/q0

The Attempt at a Solution

As far as I know to solve for this problem Fe must be equal to 0?

Or we should first resolve the forces acting on the ball, which is

T cos(37) - mg = 0.. am I right? I don't know what's next

 

[CompuChip]

So in this type of problems, you always treat the horizontal and vertical components separately. Or, in this case, you would use components along and perpendicular to the string.

Let's start by identifying all the forces working perpendicular to the string.