1. The problem statement, all variables and given/known data http://i.imgur.com/YMuGM.png 2. Relevant equations [itex]\tau[/itex] = F * r 3. The attempt at a solution I don't know how to do these types of problems. My professor didn't even go over this. He just said to use that formula to find the answer. I know the electric field multiplied by charge is equal to force. In one of the problems the field is pointing downwards and the charge is negative. So I assumed a negative charge multiplied by a field pointing in the negative y direction would result in a force pointing in the positive y direction. That's all I can come up with.