Electric Potential - Work: Negative or Positive

[Peter G.]

Hi guys,

So, these two formulas are making me very confused:

U_E=kQq/r

ΔU_E=-W_E

Ok, here is the problem:

Let's imagine that we have two positive charges. One of them is static, the other one can move.

If we place the positive charge close to the source charge, the movable positive charge will be repelled, that is, the source charge will be doing work on it. However, as it moves away, its Potential energy decreases. How can work be done on something and that same object lose energy?

Thanks!

 

[voko]

It does not lose energy. It exchanges its potential energy for its kinetic energy.