1. A moving proton has 6.4 x 10-16 J of kinetic energy. The proton is accelerated by a potential difference of 5 000 V between parallel plates. The proton emerges from the parallel plates with what speed? a) 1.3 x 106 m/s b) 8.8 x 105 m/s c)1.8 x 106 m/s d) 9.8 x 105 m/s 2. Relevant equations [itex]\Delta[/itex]Ek + [itex]\Delta[/itex]Ep = 0 3. The attempt at a solution Eki + Ekf = -Ep 6.4×10-16 + 1/2mv2 = -Q[itex]\Delta[/itex]v v= √ [(-1.6x10-19×-5000)-6.4x10-16 ×2 / 1.67x10-27] = 437740.5241... My answer doesn't match with any of the responses. What did I do wrong?