Physics Electric Field Problem

[asheik234]

Homework Statement

Three charges are set in the plane of the page so that they form the vertices of a right triangle of lengths a = 3 meters, b = 4 meters, and c = 5 meters. The charges |Q1| = 2.40 10^-3 C and |Q2| = 1.80 10^-3 C have unknown sign. Charge q = -4. 10^-4 C has a total electric force F directed upward due to the other two charges.

Determine the magnitude of the electric field at the position of q due to the other two charges.

Homework Equations

k = 9 × 109 N m2/C2
E=kq/d^2

The Attempt at a Solution

I know that the charges Q1 and Q2 are negative, thus the electric field is going towards them, but I'm not sure what to do after this, any help would be appreciated.

 

[haruspex]

Can you work out the force on q (magnitude and direction) due to each of Q1, Q2 separately?

 

[asheik234]

Yes, I found the force from Q1 to be 1350000, and the force from Q2 to be 1800000. I'm not sure what to do after this though.

 

[haruspex]

Yes, I found the force from Q1 to be 1350000, and the force from Q2 to be 1800000. I'm not sure what to do after this though.

You have two forces, and you know their magnitudes and directions. Do you know how to add vectors?