The question's diagram shows the magnetic field pointing into page, so I suppose its a "trick" question. Nevertheless, thank you for your help. I spent a long time looking at this because its the last question on the list.
Homework Statement
A stone with a negative net charge of 0.010C is given a constant horizontal motion in a uniform magnetic field in the direction pointing into the page. The field's strength is 1.70T. How fast does the stone have to move in order for it to remain moving horizontally, without...