1. The problem statement, all variables and given/known data Basically there are 3 plate capacitors, with a distance a between the first two and b between the last two. In between the first two plates is voltage V. A particle of charge q is released from the first plate, and when it leaves the second plate it is no longer accelerating. There is a magnetic field of B in the second part, and then a hole of radius r at the third plate, find the distance that the particle drops due to the magnetic field. I neglected to outline this specifically in the picture, but basically it is the distance of the bottom black line and could be called "d" 2. Relevant equations U=K F=qv x B Sum F = ma a=v^2/r E=qV 3. The attempt at a solution First I had to find the velocity of the particle at the point of the first plate, and did this using conservation of energy. U=K qV=.5mv^2 v=sqrt(2qV/m) Second, is finding the radius of the circle in the second part, using F=ma and angular acceleration Then Sum F = ma, only force is magnetic qv x B = ma qv x B = m(v^2/R) R=m*v^2 / q*v*B R=m*(2qV/m) / q*B*sqrt(2qV/m) R=2V/Bsqrt(2qV/m) At this point I have the radius R of the circular path that the magnetic field induces, but I'm totally lost at this point. I'm assuming it's just geometry of some fashion. Really would appreciate help.