Is it Final Value Minus Initial Value for Potential Energy Change in Physics?

  • Context: High School 
  • Thread starter Thread starter C. Long
  • Start date Start date
Click For Summary

Discussion Overview

The discussion centers on the calculation of the change in potential energy in physics, specifically whether it is determined by subtracting the initial value from the final value or vice versa. The scope includes conceptual understanding and clarification of conventions in physics related to potential energy and possibly kinetic energy.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant asserts that the change in potential energy is calculated as the final value minus the initial value, reflecting their learning from the Work Energy Theorem.
  • Another participant agrees with the assertion that it is final minus initial, reinforcing the same understanding.
  • A question is raised about whether the same principle applies to kinetic energy, suggesting a potential parallel in the treatment of energy changes.
  • One participant notes that while conventions on signs for state functions can be confusing, the general principle of "final minus initial" holds for changes in state.
  • Another participant advises checking the definitions used for signs in calculations, indicating that different contexts may lead to different interpretations.
  • A later reply acknowledges the previous point and indicates a willingness to verify the source of confusion regarding the online homework.

Areas of Agreement / Disagreement

Participants generally agree that the change in potential energy is calculated as final minus initial, but there is some uncertainty regarding the conventions and definitions that may affect this understanding. The discussion remains somewhat unresolved due to differing interpretations of the online homework context.

Contextual Notes

There are limitations regarding the definitions of terms and the assumptions underlying the calculations, which may vary based on context. The discussion does not resolve these ambiguities.

C. Long
Messages
10
Reaction score
0
I have a very simply Physics question. When talking about the change in Potential Energy it is the Final value minus the initial value correct? That's the way we were taught the Work Energy Thereom but some of the online homework now seems to be subtracting the Final value from the Initial. Am I wrong in my original thinking? It has been awhile since the first part of Physics for me. Thanks
 
Physics news on Phys.org
C. Long said:
Final value minus the initial value
That's the way I learned it.
 
That would be the same then for Kinetic Energy as well?
 
When changing the state of a system, "Final minus Initial." Conventions on signs of particular "state functions/variables" can be somewhat muddled, but the changes themselves are "Final minus initial."
 
Just make sure you have checked the used definition for the sign, such as implicitly assumed minus is translated mathematically to ## V = -|V| ##. Can't comment further unless you provide the online page you referred to.
 
I see what you are saying, I should have thought of that myself. I'll check to see if that's what it was.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 60 ·
3
Replies
60
Views
7K
  • · Replies 3 ·
Replies
3
Views
4K
Replies
8
Views
3K
  • · Replies 4 ·
Replies
4
Views
850
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 7 ·
Replies
7
Views
11K
  • · Replies 2 ·
Replies
2
Views
1K