Charged Particles

1. Dec 13, 2014

TheExibo

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

Particles of charge q and 3q are placed 90m away from each other. A third particle is place in between them and the total electric force on this particle is zero. Determine the position of this particle.

2. Relevant equations

F(E)=(k)(q1)(q2)/(r^2)

3. The attempt at a solution

http://imgur.com/41Ngn8o

After using the quadratic formula, I get stuck with two answers and I'm sure neigh ter of them are correct. Maybe the negative sign in the forces equation is unnecessary? Thanks

2. Dec 13, 2014

Staff: Mentor

What answers did you get? Are both consistent with the constraints of the problem? Why do you think neither are correct?

No, the negative sign was not correct, but you somehow managed to cancel it out. Looks to me like your final equation was correct. (Except that you left out a y in one of the terms; I assume that was just a typo.)

You know that the direction of the forces are opposite, so you just need to set the magnitudes equal.

3. Dec 13, 2014

TheExibo

It seems the answers in the back weren't exactly correct. Thanks for checking my work!