1. The problem statement, all variables and given/known data A 1.50x10-14 kg oil drop accelerates downwards at a rate of 1.80 m/s2 when placed between two horizontal plates that are 9.40 cm apart. The potential difference between the two plates is 980 V. Determine the magnitude of the charge on the oil drop. 2. Relevant equations |E|=V/d Fnet=ma Fg=mg Fe=q|E| 3. The attempt at a solution So first I find the strength of the electric field. |E|=V/d =(980 V)/(0.094 m) |E|=1.04x104V/m Then I find the net force. Fnet=ma =(1.50x10-14kg)(-1.80 m/s2) =-2.70x10-14N Then I find the force of gravity on the drop. Fg=mg =(1.50x10-14kg)(-9.81m/s2) =-1.47x10-13N Here is where I think I am going wrong. I try to find the electric force. Fnet=Fg+Fe Fe=fnet-Fg =(-2.70x10-14N)-(-1.4715x10-13N) =1.20x10-13N Then I find the charge. Fe=q|E| q=Fe/|E| =(1.2015x10-13N)/(1.04x104N/C =1.16x10-17 C Now this answer is obviously wrong. Where am I messing up?