Homework Help: Need help with tension in a string/charged balls attached

1. Feb 3, 2005

vaxopy

Two identical small insulating balls are suspended by separate 0.25-m threads that are attached to a common point on the ceiling. Each ball has a mass of 8.0×10–4 kg. Initially the balls are uncharged and hang straight down. They are then given identical positive charges and, as a result, spread apart with an angle of 36° between the threads. Determine (a) the charge on each ball and (b) the tension in the threads.

Its been a long time since I have worked with tension.. and free body diagrams. Can someone please provide a kick for me in the right directoin? What would the diagram look like (free body/forces), and how would I go about solving this?

2. Feb 3, 2005

gnome

Given that the threads are equal length, attached to the same point at the top, and the masses and charges of the balls are equal, it would look like an isosceles triangle, and you know, or can figure out, all the dimensions. And you should be able to determine what forces apply and in what directions. What's holding you back?

3. Feb 3, 2005

MathStudent

This exact same question has been posted here before...
If you want to do it all on your own, then don't click on the link, but I figured I'd post it just in case you wanted to see it.