forces on the two charges

Two hanging balls, each with a mass of 10g, have equal charges. One ball is hung by an insulated thread. Another ball held by an insulated rod. When it is brought horizontally towards the hanging ball within .12m of the hanging ball, the suspended ball is deflected (deflection due to like charges on both balls) until the thread creates a 30 degree angle with the vertical while its distance is still .12m from the ball held with an insulated rod. At this angle, the forces are balanced.

A) Draw a force diagram for the balls

There are 3 forces acting the first ball hung by the thread.
The gravity mg, the electric force F, and the tension T from the thread.
Fro the second ball, there are gravity mg, the electric force F, and the force F1 from the rod.

B) Calculate Fgravity
The mass = 10g = 0.01 kg
The gravity mg = 0.01 * 9.8 = 0.098 N.
C) Calculate Felectric
The net force on the ball is 0.
For the red ball, decompose the tension T to the horizontal and vertical directions.
In the vertical direction,
In the horizontal direction,

D) Calculate charge on each ball.
According to Coulomb's law, the electric force from the second ball to the red ball is

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