A group of unknown charges are shown on the screen along with vectors representing the forces on each charge. You can click-drag on any charge to change its position. The absolute-value of each charge is identical and equal to 6.3 x 10^-6C; however, some of the charges are positive and some are negative.

Also shown is a small, blue, positive test charge.

What is the net charge of this distribution? You may neglect the charge on the blue test charge. C