(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two charges are separated as shown. Where would you place a -3 microCoulombs (mC) charge such that the net force on this charge is 0?

+ +

4mC 8mC

Distance between charges are 80cm apart.

2. Relevant equations

F= (k*q1*q2) / (r*r)

3. The attempt at a solution

I found out the Force on q1 ( i made q1 the 4mC charge and q2 the 8mC charger) to q2

it came to be 4.5*10^(-1) N. Same for the F for q2 on q1. Then i manipluated the equation to slove for r. Once that was established i but the -3mC charge in the equation with the 4mC charge and F being 4.5*10^(-1) giving me an approximation of .5m aka 50 cm. But that doesnt seem right, what equation im not using to get this answer?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: College Physics 2 Electricity

**Physics Forums | Science Articles, Homework Help, Discussion**