# Homework Help: Speed of electron

1. Jan 27, 2010

### huntingrdr

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

Two electrons separated by 2*10^(-10)m are released from rest. What is the speed of each electron when they are a large distance apart. (Both electrons will have the same speed.) The answer should be 1.13*10^(6)m/s.

2. Relevant equations

none

3. The attempt at a solution

I am not sure what formula to use. If I were given kinetic energy I think I could figure this one out, but can't with the info given. Any help on where to start?

2. Jan 27, 2010

### inutard

The relevant equations are the equations for electrical potential energy and kinetic energy.
At a large distance apart, all of the potential energy stored at the start (when the e- are separated by 2*10^(-10) m) have been converted to kinetic energy.

3. Jan 27, 2010

### Gear300

Some large distance probably refers to infinite. Find the initial energy of the system, which would be the electric potential energy, U. At infinite, U would mostly convert to kinetic energy, K.