A proton is released from rest at point A, which is located next to the positive plate of a parallel plate capacitor. The proton accelerates toward the negative plate, leaving the capacitor at point B through a small hole in the plate. The electric potential of the positive plate is 2100 V. Once outside the capacitor, the proton travels at a constant velocity until it enters a region of constant magnetic field of magnitude 0.10 T. The velocity is perpendicular to the magnetic field, which is directed out of the page.
(a) Determine the speed of the proton when it leaves the negative plate of the capacitor.
(b) Determine the radius of the circular path on which the proton moves in the magnetic field.