A proton is released from rest at point A in a region containing a uniform electric field of magnitude \(E = 4.0 \times 10^3 \text{ N/C}\). Point B is located a distance \(d = 0.050 \text{ m}\) directly downstream from point A along the direction of the electric field lines. Assuming electrostatic forces are the only forces acting on the proton, what is the speed of the proton when it passes point B?