- #1

PerpetuallyConfused

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## Homework Statement

Two point charges are placed on the

*x*axis.(Figure 1)The first charge, q1 = 8.00 nC , is placed a distance 16.0 m from the origin along the positive

*x*axis; the second charge, q2 = 6.00 nC , is placed a distance 9.00 m from the origin along the negative

*x*axis.

**Find the electric field at the origin, point O.**

Give the

*x*and

*y*components of the electric field as an ordered pair. Express your answer in Newtons per coulomb to three significant figures. Keep in mind that an

*x*component that points to the right is

*positive*and a

*y*component that points upward is

*positive*.

## Homework Equations

I know I have to use the equation E = kQ/r^2 and I have to calculate E for each charge.

## The Attempt at a Solution

So far I have E2 = kQ2/r2^2 and E1 = - kQ1/r1^2

I am confused on how I know when to set E = kQ/r^2 as positive or negative?