Finding charges on an equilibrium position

AI Thread Summary
To find the charge of the ball at equilibrium, the forces acting on it must be resolved, particularly the tension and gravitational force. The equation T cos(37) - mg = 0 is crucial for balancing vertical forces, while the electric force must also be considered. The electric field E is given as (3.00i + 5.00j) x 10^5 N/C, which influences the horizontal component of the forces. By treating the horizontal and vertical components separately, the charge of the ball and the tension in the string can be determined. Understanding the balance of forces is essential for solving this equilibrium problem.
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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
 
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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.
 
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