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## Homework Statement

Consider three charges arranged as shown.

What is the magnitude of the electric field

strength at a point 2.7 cm to the left of the

middle charge? The value of the Coulomb

constant is 8.98755 × 109 N · m2/C2 . Answer

in units of N/C.

## Homework Equations

I'm truly lost. I've been looking over some other places, trying to put things together, but nothing is becoming clear to me... How do the positive and negative charges affect each other? For example if I have 2 equal positive charges, the electric field should be 0 right? How do I determine it if it is 1 positive and 1 negative charge? (Both the same value -1 and +1)

## The Attempt at a Solution

I was looking at some similar problems.

E1 = 8.98755e9 x 5.6e-6 / .064^2 = 1.228766602e7. I got that distance by finding the total distance between the point 2.7 cm to the left. So 3.7 + 2.7 = 6.4. That could be very wrong, I'm not sure.

E2 = 8.98755e9 x 3.2e-6 / .047^2 = 1.301953825e7

E3 = 8.98755e9 x -1.8e-6 / .017^2 = -5.597782007

Then i just decided to add all three of those together... As I said I'm really lost, and I'm quite sure none of what I did is correct. Any help?

Edit : Sorry... I inserted a picture to show the problem.