# Point Charge accelerated by charged ring

1. Sep 21, 2009

### riincanavi1

1. A point charge Q is held in the center of a charged ring. Half of the ring is charged
uniformly with charge 2Q and the other half with 4Q. When the point charge is released, it
accelerates toward infinitum. What is the ultimate speed of the point charge?

2. Relevant equations[E=F/q]

3. Don't know where to start. I know that there is a force applied to the charge, but the separation of the ring into halves is confusing me.

2. Sep 21, 2009

### willem2

The point charge is the same distance from all those charges.

The potential energy of a point charge q near another charge Q at distance r:-kqQ/r

3. Sep 21, 2009

### riincanavi1

"The point charge is the same distance from all those charges.

The potential energy of a point charge q near another charge Q at distance r:-kqQ/r "

So in other words I should add up the charges (6Q) and then find the potential energy. Then relate potential energy to kinetic?