Timeline for Energy of an object or a system?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 25, 2021 at 13:03 | comment | added | BioPhysicist | @madness I think you are correct. You can pick $U=0$ anywhere; the only thing that matters for the physics is the change in potential energy. | |
| Aug 24, 2021 at 20:35 | vote | accept | madness | ||
| Aug 24, 2021 at 20:35 | comment | added | madness | What do you think is happening here?Suppose the object is at roof level,then the potential energy of the earth and object is being taken $0$ for reference,then we say that the potential energy of the earth and object is now $mg(-10)$.Is my thinking procedure correct? | |
| Aug 24, 2021 at 20:33 | comment | added | madness | Thanks for the clearance,i have a doubt on a slightly deviated but related topic,we know that for measuring the potential energy of an object,we are free to choose our reference level where we would assume that the potential energy of the object in that level is $0$. But let's now think rigorously in terms of a system,what do you think the other object in the system is?Is it always the earth? For example,suppose an object is $10$ meters below a ceiling. If we took the celing to be the reference level,the potential energy if that object is $mg(-10)$. | |
| Aug 24, 2021 at 19:59 | comment | added | BioPhysicist | @madness You get to decide what "the system" is. i.e. what is "internal" and "external". For example, in a collision the momentum of one object is not conserved since the force from the other object is external. But the momentum of both objects together is conserved because then the force between them is internal. The same thing happens either way; the analysis is just different. | |
| Aug 24, 2021 at 19:48 | comment | added | madness | Thank you but could you please tell me why there is nothing wrong in thinking of the object as the system? | |
| Aug 24, 2021 at 19:45 | history | answered | BioPhysicist | CC BY-SA 4.0 |