# Homework Help: Equilibrium Question

1. Feb 5, 2010

### Leo34005

1. The problem statement, all variables and given/known data

A charge of 2.9 nC and a charge of 5.8 nC are separated by 40.80 cm. Find the equilibrium position for a -5.0 nC charge.

???????? cm from the 2.9 nC charge.

2. Relevant equations

3. The attempt at a solution

F = 2.9/5.8NC/ 4(40.80)

2. Feb 5, 2010

### gabbagabbahey

Hint (1): What must the net force acting on the -5nC charge be in order for it to be in equilibrium?

Hint (2): If a point charge $q$ is placed at a point where the net electric field from all other charges is $\textbf{E}$, what is the force $\textbf{F}$ on $q$?

Hint (3): What does the superposition principle tell you about finding the net electric field at any point in space due to two point charges?

3. Feb 5, 2010

### Leo34005

Not sure, mind helping me here?

4. Feb 5, 2010

### gabbagabbahey

If you can't answer those 3 questions, you need to study your textbook. Start by looking up "equilibrium".

5. Feb 5, 2010

### Leo34005

Can i please have an answer so i can check if my answer is wrong or right?

6. Feb 5, 2010

### gabbagabbahey

No, but if you post your answer we can tell you whether it's right or wrong, and even better, if you show your work and explain your reasoning we can point out the source of any errors you are making.

7. Feb 5, 2010

### Staff: Mentor

Leo is now on a temporary vacation from the PF because of repeatedly refusing to show work in homework threads.