How Do Charges Affect Net Force Calculation?

[aChordate]

Homework Statement

The drawing shows three point charges fixed in place. The charge at the coordinate origin has a?
q1 = +8.50 µC; the other two have identical magnitudes, but opposite signs: q2 = -5.00 µC and q3 = +5.00 µC.

http://img66.imageshack.us/my.php?image=p1818mv9.gif

(a) Determine the net force (magnitude and direction) exerted on q1 by the other two charges.

(b) If q1 had a mass of 1.50 g and it were free to move what would be its acceleration?

Homework Equations

F₁₂=k|q₁||q₂|/r²


F₁₃=k|q₁||q₂|/r²

The Attempt at a Solution

F₁₂= +2.128*10²³

F₁₃= -+2.128*10²³

cos(23°)= F_x/+2.13*10^23

F_x= 1.96*10²³

cos(23°)= F_y/-2.13*10^23

F_y= -1.77 *10⁴⁶

Before I go any further, I wanted to make sure I am doing this right since I am kind of rusty. If anyone could check, it would be greatly appreciated.

Thanks in advance!

 

[Simon Bridge]

Your attempt does not show any reasoning nor any working - so I cannot tell if you are doing this right or not.

Note: you can show the image in the post like this:

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You look like you've maybe tried to break the forces into x and y components - but why not just draw the vectors head-to-tail? You can see by inspection how their magnitudes and directions are related - which should tell you the direction of the total force without having to do any trig.