electric field

[-EquinoX-]

1. The problem statement, all variables and given/known data
http://i41.tinypic.com/6r1003.jpg


Find the electric field at position (2.00, 0)

2. Relevant equations



3. The attempt at a solution

I am just confused by the question actually, does it mean at point 2 m to the right of 0,0? or is it to the left?

The way I would solve this problem is by finding the electric field that each charges made 2 m from the point, for example the -.4nC, we can find the electric field at 2.00 by ke * -.4nC/2.5^2, and as well for the others and sum them all together, am I right?

[LowlyPion]

I am just confused by the question actually, does it mean at point 2 m to the right of 0,0?

Yes. The way I read the diagram, the 5nC is at the origin and they are asking for the point 1.2 m to the right of the 3nC charge.

The way I would solve this problem is by finding the electric field that each charges made 2 m from the point, for example the -.4nC, we can find the electric field at 2.00 by ke * -.4nC/2.5^2, and as well for the others and sum them all together, am I right?

Yes. Superposition is right. The distances for each (left to right) to be clear would be 2.5, 2, 1.2 .
Mind your signs.

[-EquinoX-]

so basically it's just ke * -.4nC/2.5^2 + ke * 5nC/2^2 + ke * 3nC/1.2^2

[LowlyPion]

That's what it looks like to me.

[-EquinoX-]

What if the question now is (0, 2.00) instead of (2.00,0)?

[LowlyPion]

What if the question now is (0, 2.00) instead of (2.00,0)?

That would mean apparently it was on the y axis. In which case get out your Pythagoras.

[-EquinoX-]

I use the pythagorean theory to find the distance from the -4 and 3 charhea to the point (0, 2.00) only right?