posted by Anonymous .
The figure shows four electrical charges located at the corners of a rectangle. Like charges, you will recall, repel each other while opposite charges attract. Charge B exerts a repulsive force (directly away from B) on charge A of 4.2 . Charge C exerts an attractive force (directly toward C) on charge A of 8.4 . Finally, charge D exerts an attractive force of 2.8 on charge A.
There is no question here. There are also no units for the charges.