# Potential versus potential energy

1. Jan 22, 2006

### siifuthun

I'm still a bit confused as to what "potential" referers to when we're talking about electricity and magenetism, and I'm not quite sure how it's related to potential energy if it is. If anyone can offer a bit of clarification or just a place that offers a good definition (b/c my book sure doesn't) I'd be grateful.

2. Jan 22, 2006

### Jelfish

This is how I use to think of potential:

Say you're at home and decide to make an apple pie but you don't have any apples. It so happens there are lots of stores in your town that sell apples so you decide to look around. Store 1 sells apples for $.25 per apple. Store 2 sells apples for$.33 per apple. Say there are like 10 stores and each store sells apples for a different price per apple.

You are now wondering how much you need to spend to buy 10 apples. To do this, you must multiply 10 with the price per apple, depending on your location.

To simplify your calculation, you create a function of prices based on location. So price(store1)=.25, price(store2)=.33, etc. Therefore, knowing your location, all you need to do is multiply the number of apples you're buying and you know the total price. This price function is useful because it is independent of the number of apples you're buying.

Analogously, this price function is similar to what we call "potential" in electrostatics and gravitation. Instead of the total price of purchase, we have a potential energy. Instead of apples, we have electric charge or mass.

Electric PE = charge x electric potential
Gravitational PE = mass x gravitational potential
Total Price = apples x price-per-apple.

The potential is usually a function of location, and of course, you have equations that define what the magnitude of the potential is at a given position.

(EDIT: sorry, I mixed some terms earlier)

Last edited: Jan 22, 2006
3. Jan 22, 2006

### siifuthun

Thank you for helping me sort that out in my head, I think I was onto the right idea but that I was just confused, this really clarified it for me.

4. Feb 6, 2007

### mace2

Again, sorry to bump an old thread but Jelfish's post really helped me understand EP. I think it might help others if they see it, too.