Timeline for Potential and kinetic energy of equal objects who have reached terminal velocity from different heights
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 5, 2020 at 17:07 | vote | accept | user253214 | ||
| Feb 4, 2020 at 22:28 | comment | added | Bob D | In any case, I'm up-voting you based on the last paragraph. | |
| Feb 4, 2020 at 22:27 | comment | added | Bob D | This is one of those cases where newtonian-mechanics and thermodynamics concepts intersect. Within mechanics it is common to talk about "friction heating", whereas in thermodynamics the term "friction heating" is frowned upon. Work and heat are the two mechanisms of energy transfer. When friction increases temperature (like when you vigorously rub your hands together to feel "warm") it is really energy transfer by friction work. Heat (and heating) is not involved. Similarly when a gas is compressed its temperature increases because of work. Compression does not "heat" the gas up. | |
| Feb 4, 2020 at 21:32 | comment | added | Mark H | @BobD Thanks for the comments. Thermodynamics was always my worst subject, so I appreciate corrections. | |
| Feb 4, 2020 at 21:15 | comment | added | Bob D | I like the last paragraph. But I still don’t like statement in the first paragraph that gravity is “heating up” the object. There is no transfer of energy to the object from the air or gravity due to a temperature difference. But that’s OK I don’t mean to belabor the point since the last paragraph does the job | |
| Feb 4, 2020 at 19:36 | comment | added | Mark H | @BobD Subtle point. I've edited my answer. | |
| Feb 4, 2020 at 19:36 | history | edited | Mark H | CC BY-SA 4.0 |
More technically correct
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| Feb 4, 2020 at 15:10 | comment | added | Bob D | Heat is energy transfer due solely to temperature difference. Heat is not the energy itself but a mechanism for transferring energy, the other being work. Heat is not "conserved". The energy being transferred is conserved. Instead of "heating up", it's better to say the friction of air resistance raises the temperature of the object (its internal energy). Once the temperature of the object is raised above the temperature of its surroundings, then heat transfer can occur between the object and its surroundings. | |
| Feb 4, 2020 at 5:49 | history | answered | Mark H | CC BY-SA 4.0 |