Electric Field and Magnitude Problem

[pstir2]

Homework Statement

Two identical point charges, q1 = +2.5 x 10-6 C and q2 = +2.5 x 10-6 C, are placed as shown in the diagram below. Point P is a distance 0.05 m from q1 and 0.12 m from q2, such that the angle at P is 90 degrees. Calculate the magnitude of the Electric field E at point P.

Homework Equations

Not sure which of these rules would apply. Also I suck at vectors
F = k x q1 x q2 / r^2

E = k x Q / r^2

The Attempt at a Solution

So I have created the diagram and I believe I have to use the second formula twice, along with some trigonometry, but I'm not sure.

E1 = k x Q1 / r^2
E1 = k x +2.5 x 10^-6 / 0.05^2
E1 = 9 x 10^6

E2 = k x Q2 / r^2
E2 = k x +2.5 x 10^-6 / 0.12^2
E2 = 1.563 x 10^6

I Can't do vectors at all. Please help.

 

[td21]

Step 1:
Decompose the E field you got at point P due to q1 to horizontal and vertical components.
Do the same for E field you got at point P due to q2.

 

[Doc Al]

So I have created the diagram and I believe I have to use the second formula twice, along with some trigonometry, but I'm not sure.

That's exactly correct.

Keep going! Find the field from each charge, then find the resultant field by adding the vectors.