A constant electric field with magnitude 1.50 ✕ 103 N/C is pointing in the positive x-direction. An electron is fired from x = −0.0200 m in the same direction as the electric field. The electron's speed has fallen by half when it reaches x = 0.150 m, a change in potential energy of 4.08 ✕ 10−17 J. The electron continues to x = −0.200 m within the constant electric field. If there's a change in potential energy of −8.40 ✕ 10−17 J as it goes from x = 0.150 m to x = −0.200 m, find the electron's speed (in m/s) at x = −0.200 m. Hint