Homework problem 18.5
18.5  
Consider three identical metal spheres, A, B, and C.
Sphere A carries a charge of +5q. Sphere B carries a charge of -q.
Sphere C carries no net charge. Spheres A and B are touched
together then separated. Sphere C is then touched to sphere A and separated
from it. Last, sphere C is touched to sphere B and separated from it.
- How much charge ends up on sphere C?
What is the total charge on the three spheres
- before they are allowed to touch each other and
- after they have touched?