# I need some guidance on my coulomb's law homework.

## Homework Statement

two charged particles held fixed in the xy plane are: q1= +3.0 μC, x1=3.5 cm, y1= 0.50 cm, and q2= -4.0 μC, x2= -2.0 cm, y2= 1.5 cm.

(question 1) What is the magnitude and the direction of the electrostatic force on q2. ?

(question 2) Where would a third charge q3= +4 μC be placed so that the net electrostatic force on q2 is zero?

## Homework Equations

For question one i came out to 0.025N @144° ccw
is that even remotely correct?

## The Attempt at a Solution

I don't want the answer, i would like to just know the steps so that i can try it for myself.
Ive added the x's amd y's and came out with

Ʃ x= 0.035-0.02= 0.015
Ʃ y= 0.005+0.015=.02

from here what can i do ?
could i just inverse the angle from q2 to find the position?

CAF123
Gold Member
Can you show your working for how you get 0.025N at 144o counterclockwise?

SammyS
Staff Emeritus
Homework Helper
Gold Member

## Homework Statement

two charged particles held fixed in the xy plane are: q1= +3.0 μC, x1=3.5 cm, y1= 0.50 cm, and q2= -4.0 μC, x2= -2.0 cm, y2= 1.5 cm.

(question 1) What is the magnitude and the direction of the electrostatic force on q2. ?

(question 2) Where would a third charge q3= +4 μC be placed so that the net electrostatic force on q2 is zero?

## Homework Equations

For question one i came out to 0.025N @144° ccw
is that even remotely correct?

## The Attempt at a Solution

I don't want the answer, i would like to just know the steps so that i can try it for myself.
Ive added the x's amd y's and came out with

Ʃ x= 0.035-0.02= 0.015
Ʃ y= 0.005+0.015=.02

from here what can i do ?
could i just inverse the angle from q2 to find the position?
Why are you adding the x coordinates and adding the y coordinates ?

The distance between points, (x1, y1) and (x2, y2) is $d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\ .$