Ok, an ion experiences a magnetic force of 6.2X10^-16 N when moving in the positive x direction, but no force when moving in the positive y direction. What is the magnitude of magnetic force exerted on the ion when it moves in the x-y plane along the line x=y? Assume the ions speed is the same in all cases. I know that for this problem F=qvB sin theta. Because the ion travels on the line x=y, then the theta angle is 45. Other than that I have no clue. Thanks again for any help.