An Electron Is Projected Horizontally with a Speed of 5

An electron is projected horizontally with a speed of 5.0 × 10⁶ m exactly in the middle of two parallel plates at potentials of −40 V and 104 V, respectively. The plate separation is 3.0 cm. The plates are long enough that the electron, rather than passing completely between the plates, eventually strikes the plate sitting at 104 V potential. What is the speed of the electron when it strikes the plate? The mass of the electron is 9.11 × 10⁻³¹ kg.

A) 8.7 × 10⁶ m/s
B) 7.1 × 10⁶ m/s
C) 6.0 × 10⁶ m/s
D) 5.0 × 10⁶ m/s