If the particle experience a costant force then theacceleration
along the y direction is
         ay
= e E / m
             =
(15×10-3 C)(4.5 N/C) / (1.17*10-7 kg )
             =
5.76×105 m/s2
Using the equation Vy = Voy+ ay
t
                                Vy=   ayt           [  Voy
= 0]
                                    =
(5.76×105 m/s2 )(0.7s)
                                     =
4.03×105 m/s
  As Vx and Vz =0 so the speed is 4.03×105
m/s
