Change in Grav PE with the change in origin.

  • Thread starter Thread starter mrhingle
  • Start date Start date
  • Tags Tags
    Change Origin
Click For Summary

Homework Help Overview

The discussion revolves around gravitational potential energy (PE) and how it is affected by the choice of reference point or origin. Participants explore the implications of moving the origin of the potential energy measurement in relation to an object's height and its subsequent fall to the ground.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question how the change in the reference point affects the calculated potential energy of an object as it falls. There is an exploration of whether moving the origin leads to negative values for potential energy and how changes in potential energy are defined.

Discussion Status

Some participants have provided insights regarding the relativity of potential energy to the chosen reference point. There is an ongoing exploration of the concept of change in potential energy and whether it can be considered negative in different scenarios. Multiple interpretations of the problem are being discussed.

Contextual Notes

There is a focus on the definitions and assumptions regarding potential energy and its reference points, with participants examining the implications of these choices on the calculations involved.

mrhingle
Messages
21
Reaction score
0
If a 1kg object is 1.5 m heigh. I find its PE to be 14.7 J. If it falls to the ground, the PE of 14.7 J goes to 0 as the object approaches the ground. Right?

Now say the origin has been moved to 1.5 m where the object lies. Is the object at 0 J at the origin and approaching -14.7 J as it approaches the ground?

Thanks
 
Physics news on Phys.org
mrhingle said:
If a 1kg object is 1.5 m heigh. I find its PE to be 14.7 J. If it falls to the ground, the PE of 14.7 J goes to 0 as the object approaches the ground. Right?

Now say the origin has been moved to 1.5 m where the object lies. Is the object at 0 J at the origin and approaching -14.7 J as it approaches the ground?

Thanks

Hi mrhingle, welcome to PF.

Yes, changes in PE are relative to a chosen zero reference. If you place the zero reference for PE at an origin at a given height, then excursions below that height are associated with negative values for the PE.
 
Would both cases be a negative change in PE?
 
mrhingle said:
Would both cases be a negative change in PE?

ΔPE = PEfinal - PEinitial

If ΔPE is positive then the change is positive. If ΔPE is negative then the change is negative.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 56 ·
2
Replies
56
Views
3K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 37 ·
2
Replies
37
Views
5K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
1
Views
3K
  • · Replies 9 ·
Replies
9
Views
8K