Two identical conducting spheres, A and B, carry equal charge. They are stationary and are separated by a distance much larger than their diameters. A third identical conducting sphere, C, is uncharged. Sphere C is first touched to A, then to B, and finally removed (to a far away distance). If before the sphere C is introduced the electrostatic force between A and B is Fi , how does Ff , the electrostatic force between A and B after C is removed, compare to Fi?

8F_i = 3F_f

Explanation:

When two identical spheres are touched to each other, they equally share the total charge. Therefore, When neutral C is first touch to A, they share the initial charge of A equally.

Let us denote that the initial charge of A and B are Q. Then after C is touched to A, their respective charges are Q/2.

Then, C is touched to B, and they share the total charge of Q + Q/2 = 3Q/2. Their respective charges afterwards is 3Q/4 each.

The electrostatic force, Fi, in the initial configuration can be calculated as follows.

he kicked it 10 feet straight up into the air? i think this works.

see earlier answer