Three identical point charges in an equilateral triangle.?

You know the formula for calculating the force on a particle do to other particles pushing on it. You calculate this force using formula that takes into consideration the magnitude, position, and quantity of each charge that is doing the pushing, then adding up each individual charge to calculate the overall push.

1. Take one point of your charge triangle and put it on the x-axis at x = 0.1m.

2. Take the other two points and put then above origin at y = 0.05 m and below at y = -0.5 m.

3. You are going to see how hard the two charges at origin are pushing on third charge.

4. By intuition, charges at x = 0 fight with each other to push third charge up and down, thus, cancelling each other out, so they will only push outward, causing third charge to never change its y coordinate from 0, but increase its x coordinate as it is being pushed.

5. By intuition, the force vectors of each charge on y axis is reduced..the amount being not the full distance 0.1m, but the distance from y axis to third charge, or, the height of triangle.

7. And since there are two charges pushing, you have 2Q.

So answer is to take standard formula for Q, compute force for that one Q, take the component of vector that is in parallel with x-axis, which means reducing force by multiplying it by a fraction according to height of triangle, then doubling it, since there are two Q's pushing on third Q.