# Parallels between potential energy in mass/charge

To understand potential energy in mechanics it's easy to show something like this:

Here the potential energy of the object is 1kg * 1m * g.

Now to demonstrate this same thing with electrical potential energy, let's call the floor/ground 0V, and the positive terminal of a battery the ball.

Using the ball parallel, what would the + terminal of the battery be in the above picture -- would that be the ball? What about the "1m above ground" -- is there some similar conception in electricity? I would like to have a more intuitive understanding (such as a ball dropping).

• its voltage: energy of charge $q V$=$q h E$ where$E$ is the constant electric field analogus to $g$ – lineage Feb 2 at 0:06
• @lineage what is h ? – David542 Feb 2 at 0:07
• h is height above -ve terminal – lineage Feb 2 at 0:08
• @lineage thanks. So basically it's 'similar to' mgh = qEh, where E is like gravity, mass is like charge, and height is height? Also, what does the e in -ve stand for (negative voltage, but e?) – David542 Feb 2 at 0:10
• short for negative – lineage Feb 2 at 0:34

## 1 Answer

There is indeed an analogy between gravitational potential energy and electrical potential energy.

The increase in gravitational potential energy in raising your ball of mass $$m$$ a height $$h$$ is $$mgh$$.

The increase in electrical potential potential energy in moving a charge $$Q$$ from the negative to positive terminal of the battery with voltage $$V$$ is $$QV$$.

Hope this helps.

• thanks for this. Why then is a charge particle, Q, not the base unit for electricity, but rather Amps? It seems the "charge particle" would be the equivalent of the "mass object"? – David542 Feb 2 at 0:07
• The basic unit of electricity is the ampere, but the ampere is further defined in more basic terms, namely the amount of charge Q in Coulombs that crosses a surface per second. – Bob D Feb 2 at 0:35
• @David542 Incidentally, according to Wikipedia, the earlier CGS measurement system used electric charge (coulomb) as the base unit. The ampere was then defined as one coulomb of charge per second. In the SI system the unit of charge, the coulomb, is defined as the charge carried by on ampere during one second. Alas, things change. – Bob D Feb 2 at 19:58