Electrical Potential, Voltage, Work

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Discussion Overview

The discussion revolves around the concepts of electrical potential energy, voltage, and work, as presented in a specific physics textbook. Participants are exploring the relationships between these concepts, particularly focusing on the equations provided in the text and their implications.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant questions the reasoning behind the calculation of electrical potential energy (EPE) as the first point minus the second point in equation 19.2, seeking clarification on why this approach is taken.
  • The same participant expresses confusion regarding the relationship between voltage and work, specifically asking if voltage is defined as negative work divided by charge.
  • Another participant suggests that the original poster should type out the equations for clarity, as not everyone may have access to the textbook.
  • A different participant reiterates that voltage is defined as potential energy divided by charge, and notes that the change in voltage is related to work divided by charge.

Areas of Agreement / Disagreement

The discussion contains multiple viewpoints regarding the definitions and relationships between electrical potential energy, voltage, and work. There is no consensus reached on the questions posed, and participants are exploring different interpretations of the equations.

Contextual Notes

Participants have not provided specific equations in detail, which may limit the clarity of the discussion. The understanding of voltage and work appears to depend on interpretations of the equations presented in the textbook.

chembloke
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Hi guys,

So my question is related to Electical Potential Eenrgy and Voltage. First off, I am using the Physics book by Cutnell, 8th Edition. If anyone would like to turn to the page I am on, it is page 570 or around there if you have the newer edition.

So, they first relate Work by equation 19.2 as shown below, and then Voltage by equation 19.3. So i get that part, sorta.

But when it comes to Voltage, as shown in equation 19.4, is Voltage (negative) Work divided by charge?

in equation 19.2, they use EPEA-EPEB, but why not the other way around.
Then 19.4 calcualtes Voltage by using EPEB-EPEA, but Work is now negative.

equations.jpg


So i guess my main question -- in 19.2, why is EPE calculated as the first point minus the second point, and not the other way around?
The other question relates to Voltage and negative work? I've read the section twice now and it is still not sticking.

Sorry if my question is complicated, I'll try to answer any questions you have about my question. :-p

Thank you!
 
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You should probably type out the equations. Most people do not have your textbook.
 
Not sure if the equations are showing in the original post, but here they are in case they are not showing up.

bga493.jpg
 
chembloke said:
Is Voltage (negative) Work divided by charge?
Voltage is the potential energy divided by charge. The change in voltage is related to work divided by charge.
 

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