Hello please I am having some issues understanding these 5 questions please can someone explain it to me?

1. A tiny, glass sphere has a charge of +24.3 nC. A metal ball bearing, which is 4.00 cm above the glass sphere, experiences an electric force of magnitude 0.0130 N. What is the ball bearing's charge? Assume it is positive.

2. In the figure below, the distance between charges A and B and the distance between charges B and C are both 6.00 cm.

If A = 5.00 nC, B = -6.50 nC, and C = 4.50 nC, what is the magnitude net electric force on A? (image below)

A + B C +10 nC 10 nc + b a + 5.0 nC+ 4.0 cm 2.0 cm 3.0 cm 3.0 cmH = 1.0 m 1.0 m