Timeline for Doubt in rotational work-energy theorem
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
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| Mar 29 at 12:16 | history | edited | Qmechanic♦ | CC BY-SA 4.0 |
deleted 4 characters in body; edited tags; edited title; edited tags
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| Mar 29 at 12:12 | history | reopened |
gandalf61 Michael Seifert Thomas Fritsch |
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| Mar 29 at 11:13 | review | Reopen votes | |||
| Mar 29 at 12:12 | |||||
| Mar 29 at 11:13 | comment | added | gandalf61 | Voting to reopen. Since the solution is already given, this is clearly a conceptual question about understanding the solution and not a "do my homework for me" question.. | |
| Mar 29 at 4:59 | history | closed |
Bob D John Rennie Hyperon |
Not suitable for this site | |
| Mar 28 at 21:03 | history | became hot network question | |||
| Mar 28 at 17:14 | vote | accept | yyzr | ||
| Mar 28 at 17:14 | comment | added | yyzr | Oh I'm sorry, I was making a mistake in the integration else I would have understood it much before, thank you | |
| Mar 28 at 16:55 | comment | added | gandalf61 | @yyzr It is not wrong, it is just a different route to the same answer. The torque exerted by the rod's weight at an angle $\phi$ to the vertical is $-\frac {mgl} 2 \sin \phi$ and if you integrate this from $\phi=0$ to $\phi = \theta$ you get $\frac {mgl} 2 (\cos \theta - 1)$, so the work done against gravity comes to the same value either way. | |
| Mar 28 at 16:02 | answer | added | gandalf61 | timeline score: 6 | |
| Mar 28 at 14:19 | review | Close votes | |||
| Mar 29 at 4:59 | |||||
| Mar 28 at 14:00 | comment | added | yyzr | Does the gravity not impart a torque on the system? I find the torque -mgLcos(x)/2, hence upon integrating I find its rotational work. Why is it wrong to do so? | |
| Mar 28 at 14:00 | history | edited | Bob D |
edited tags
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| Mar 28 at 13:42 | comment | added | Jon | The only component doing work by gravity is the one the book accounts for. | |
| Mar 28 at 13:23 | comment | added | yyzr | So does the gravity not to any rotational work? I find its value -mgLsin(x)/2 | |
| Mar 28 at 13:17 | comment | added | Jon | The book takes into account just the forces that do work and enter into the energy balance. | |
| Mar 28 at 13:03 | history | asked | yyzr | CC BY-SA 4.0 |