# Homework Help: Force on charge and electric field question

1. Jul 12, 2012

### XodoX

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

http://img521.imageshack.us/img521/1996/physicsz.jpg [Broken]

2. Relevant equations

3. The attempt at a solution

I hope the drawing is somewhat clear. How do I find the force on the charge g0 and the electric field at the origin due to the charge bar? There's barely any information given. The first λ is at 7m and the second one at 10m. And you have 2 C at the origin. I do not know how to do this. I hope somebody can help me with this.

Last edited by a moderator: May 6, 2017
2. Jul 12, 2012

Hi,
A bit more information might be helpful. Is the bar a continuous line of charge, or two point charges separated by 3 metres. In the former case you need to integrate along the bar using for example Coulomb's law. In the latter case you just need to sum the forces from the two charges.

3. Jul 13, 2012

### XodoX

No idea. Looks like it has to be 2 separate charges. Otherwise, I wouldn't know what that would be. Can't find anything that would apply to that. I guess I will go with Coulomb's law then.

4. Jul 13, 2012

### pgardn

From your drawing and notations it looks like you have two diff. linear charge densities for two parts of the bar. So integration is necessary to find the Efield at the origin. After that you just do F =qE You would then know the electric field strength at the 2C charge so you got the force.

Have you gone this far in your course?