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Energy=work, but how does work = electric potential energy?

by malinarn
Tags: electric, energy, energywork, potential, work
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malinarn
#1
Nov17-11, 09:06 AM
P: 5
yes, energy = work, but how does electric potential energy (U) = Vq (electric potential and charge) relate to work (W=Fd), specifically. An example would be most helpful!
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ZapperZ
#2
Nov17-11, 09:14 AM
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Back up a bit. Do you also have a problem relating work to gravitatonal potential energy, which I presume, you've encountered already?

Zz.
malinarn
#3
Nov17-11, 09:32 AM
P: 5
So gravitation potential energy is the same as electrical potential except it's a different source (the field versus the mass of the earth)? I think i understand this, I guess a better question would be how to relate the SI units of work and energy. I know that they are related, but how (Volts * q) which equals electric potential energy relates to Work (Fd) is beyond me. any ideas?

malinarn
#4
Nov17-11, 09:52 AM
P: 5
Energy=work, but how does work = electric potential energy?

geez i think i figured it out. the SI unit of energy is Joules. Joules also equals newton*meters. Work is force*distance, which is also Newton*meters, so all that makes sense. Then electric potential energy (U)=V*q or electric potential and charge. (sorry I got it wrong above). well, volts also equals J/C. so when you cancel the coulombs with the charge in the equation you're left with just Joules! that's how regular old energy relates to electric potential energy, then how to relate energy to work. well, work is Fd and energy is newton meters (or force* distance). so that's it right? this may have been stupid and really pointless, sorry for that...but I did learn here (if all this is even right?)! haha thanks for your help connecting ideas!
ZapperZ
#5
Nov17-11, 09:57 AM
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It is not stupid and pointless. And this illustrate my philosophy in teaching, in which you learn new things on top of things you already know. That's why I wanted to ask you if you are already OK with gravitational potential energy, because if you are, then the electrostatic potential energy is no different other than mass being replaced by charge.

The BEST learning method is when, with some help, you discover for yourself the solution to the problem you face. I merely tried to guide you so that you can do this for yourself. Next time, when you encounter a problem, you will learn this technique of thinking where you try to see if there have been something similar that you've encountered before that can guide you to tackle the new problem.

Zz.


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