A particle leaves the origin with a speed of1 × 106 m/s at 30? to the x axis. It moves in a constant electric field E = Eyˆj. Find Ey such that the particle will cross the x axis at x = 2.5 cm if the particle is an electron. The fundamental charge is 1.602 × 10-19 C, and the masses of the electron and proton are 9.11 × 10-31 kg and 1.6726 × 10-27 kg, respectively.