Please solve completely for me to understand. Thanks.

Two ping pong balls having equal charges and equal masses of 0.250 grams are suspended from a nail by nylon threads 125 cm long. Electrostatic repulsion keeps them 200 mm apart. Calculate the charge on each ball. Find the direction and magnitude of the net electrostatic force exerted on the point charge q2 in the following figure. (b) How will your answer change if the distance d were tripled? (Note: For three charges, given q= +12 C and d= 16 cm.) 91 = +9 92=-2.09 93=+3.0q 3 charges, 1.0 JC each, are located on three vertices A, B, C of an equilateral triangle with sides 2 cm each. Another charge q is located at the midpoint of the side BC. Calculate q so that net force on the charge at A due to the charges at B, C and D is zero. 1.0 UC 2cm 2cm 1.0 HC 1.0 HC