It <span>Ions were once atoms with the same number of electrons and protons. Since they have opposite charges atoms are neutral. When they become ions the lose or gain electrons and become unbalanced. ... These different charges are attracted to each other via electric forces.</span>
Power is the work done per unit time. Therefore,

Therefore,
I assume that the ball is stationary (v=0) at point B, so its total energy is just potential energy, and it is equal to 7.35 J.
At point A, all this energy has converted into kinetic energy, which is:

And since K=7.35 J, we can find the velocity, v:
The answer should be C) Slide against each other.
Medicine to a patient. That should be calculated based on weight, strength/dosage and possibly other factors