## anonymous one year ago Three point charges are arranged on a line. Charge q3 = +5.00nC and is at the origin. Charge q2 = -2.50 nC and is at x = 4.00 cm . Charge q1 is at x = 1.50 cm . What is q1 (magnitude and sign) if the net force on q3 is zero?

1. anonymous

$F _{e}=k _{e}\frac{ q1q2 }{ r^2 }$ is the formula where $k _{e}=8.9\times10^9$

2. anonymous

Yes, I was able to get that far. :) I am just not sure where I messed up. Let me see if I can post the work that I have already done...

3. anonymous

|dw:1441329766590:dw|

4. anonymous

So $k _{e}\frac{ q2q3 }{ r^2 }+ k _{e}\frac{ q1q3 }{ r^2 }=0$ You know your values for all those variables except q1

5. anonymous

|dw:1441330202254:dw|

6. anonymous

$k _{e}(\frac{ q2q3 }{ r^2 }+\frac{ q1q3 }{ r^2})=0$

7. anonymous

$\frac{ q2q3 }{ r^2 }+\frac{ q1q3 }{ r^2 }=0$