In an inkjet printer, letters are built up by squirting drops of ink at the paper from a rapidly moving nozzle. The ink drops, which have a mass of 1.3 10-8 g each, leave the nozzle and travel toward the paper at 21 m/s, passing through a charging unit that gives each drop a positive charge q by removing some electrons from it. The drops then pass between parallel deflecting plates 2.0 cm long where there is a uniform vertical electric field with magnitude 7.7 104 N/C. If a drop is to be deflected 0.35 mm by the time it reaches the end of the deflection plates, what magnitude of charge must be given to the drop? So, I know that F= E*q=m*a I can solve for t, . I still don't know a, the acceleration, or vfinal of y either. I was thinking of solving for vfy by using dy=vi+vf/2 * t. Either way, I keep getting the wrong answers. They are supposed to be about ^-13. Any help is appreciated!!