# Finding the distance between two charges

watabi

## Homework Statement

The potential energy of a system of two charges (q1 = 5.0 µC and q2 = 3.3 µC) is 0.37 J. What is the distance between the charges?

## Homework Equations

U=(kq_0q)/r --> r=U/(kq_0q)

U=V/q_0

V=0.37J
q1 = 5.0 µC
q2 = 3.3 µC

## The Attempt at a Solution

So I was going to use equation 2 but I have two charges involved and that one only asks for q_0.
Do I calculate the change of the charge and use that for q_0?

## Answers and Replies

LittleMrsMonkey
V is potential.
U is potential energy.

watabi
V is potential.
U is potential energy.

Wow, that cleared up a lot so,

r= 0.37J/((8.99e9)(5e-6)(3.3e-6)) ?

LittleMrsMonkey
Try solving for r again,you've made a mistake.

watabi
Try solving for r again,you've made a mistake.
Was it the micro?

LittleMrsMonkey
No.And it's the correct equation.The fraction is mot correct,though.

LittleMrsMonkey
Seeing it in this form might help you: ##U=\frac{q_1q_2}{r} ##
So,does ##r=\frac{U}{q_1q_2} ##?