# Velocity of two equal charges placed by one another

1. Jan 24, 2012

### tcbarr

1. The problem statement, all variables and given/known data
Two identical 8.5 point charges are initially 4.5 from each other.

If they are released at the same instant from rest, how fast will each be moving when they are very far away from each other? Assume they have identical masses of 2.0 .

2. Relevant equations

3. The attempt at a solution
So I can calculate the force they will exert on each other at this distance using coulombs law F=k(Q1Q2/r^2) but I don't know how to translate this to velocity. help me, I'm so bad a physics!!

2. Jan 24, 2012

### SammyS

Staff Emeritus
Hello tcbarr. Welcome to PF.

You need to include the units that go with all of those numbers! It's impossible to solve this problem without them.

Rather than solving this using the Coulomb Force, I suggest you solve it using Electric Potential and Conservation of Energy.

3. Jan 24, 2012

### tcbarr

Thanks! I just copied and pasted the question didn't realize that they got droped. charges were micro coulombs and mass was grams. I'll try it in a bit using Electrical potential and conservation.