# Electric force angles problem

1. Mar 30, 2008

### Bensky

Electric force angles problem :(

1. The problem statement, all variables and given/known data
Three positive particles of charges 11.0 µC are located at the corners of an equilateral triangle of side d = 14.0 cm (Fig. 16-38). Calculate the magnitude and direction of the net force on each particle.

Fig. 16-38

2. Relevant equations
F = KQ_1Q_2/r^2

3. The attempt at a solution
F = KQ_1Q_2/r^2
F = (9X10^9)(1.1X10^-5)^2/.14^2
F = 55.561 N for all points - Q1, Q2, and Q3 (correct)

Q1 angle = 90 degrees (correct)
Q2 angle = ?
Q3 angle = ?

I need to find the directional angle for particles Q2 and Q3 - I am unsure how to find these. I was thinking I might have to draw a triangle?

Thanks,
Bensky

2. Mar 30, 2008

### rocomath

It's an equilateral triangle.

$$\angle Q_1=\angle Q_2=\angle Q_3$$

$$\angle Q_1+\angle Q_2+\angle Q_3=180$$

3. Mar 30, 2008

### Bensky

I'm not looking for the interior angles, I'm looking for the angle of direction of force on Q2 and Q3.