Before you set out to calculate power, it's helpful to identify what you hope to calculate. There are four calculations, each of which is a
pathway for the power.
Whenever power is shifted using an electrical circuit, expect to find an electrical pathway: the pathway is
Power in the electrical working pathway.
Both voltage or potential difference and current set the power in the electrical pathway. So you can get a high power either by choosing a high current or a high potential difference—there is a trade-off.
Since both force and velocity can be negative, so the power can also be negative.