Timeline for What makes a wrist-energized gyroscope rotate faster?
Current License: CC BY-SA 3.0
21 events
| when toggle format | what | by | license | comment | |
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| Oct 14, 2014 at 15:50 | vote | accept | fgrieu | ||
| Jul 23, 2014 at 3:51 | history | edited | fgrieu | CC BY-SA 3.0 |
Measurement of diameters with a caliper; report top speeds, clarify Q1.
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| Jul 23, 2014 at 3:45 | history | edited | fgrieu | CC BY-SA 3.0 |
Measurement of diameters with a caliper; report top speeds, clarify Q1.
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| Jul 23, 2014 at 3:39 | history | edited | fgrieu | CC BY-SA 3.0 |
Measurement of diameters with a caliper; report top speeds.
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| Jul 22, 2014 at 8:46 | history | edited | fgrieu | CC BY-SA 3.0 |
Remive whobling
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| Jul 22, 2014 at 8:38 | history | edited | fgrieu | CC BY-SA 3.0 |
Mention three modes
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| Jul 22, 2014 at 7:37 | history | edited | fgrieu | CC BY-SA 3.0 |
Try a quantitative approach to confirm rolling
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| Jul 22, 2014 at 6:54 | history | edited | fgrieu | CC BY-SA 3.0 |
friction is instrumental in spinning-up the rotor
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| Jul 22, 2014 at 6:42 | history | edited | fgrieu | CC BY-SA 3.0 |
Polish
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| Jul 22, 2014 at 6:35 | history | edited | fgrieu | CC BY-SA 3.0 |
State diameter of shaft and whasher
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| Jul 22, 2014 at 0:48 | answer | added | BowlOfRed | timeline score: 6 | |
| Mar 17, 2014 at 22:58 | history | tweeted | twitter.com/#!/StackPhysics/status/445695733984161792 | ||
| Mar 17, 2014 at 12:06 | comment | added | fgrieu | @user3058846: when something gains speed by friction (in some Galilean referential), in all examples I know, this is thanks to something with a faster speed (in that referential). As tentatively explained in the updated question, I do not see that this is the case here, at least if I consider rotation along the rotor's axis (which, admittedly, is not speed gain in a proper Galilean referential; perhaps what I perceive as a paradox comes from that). | |
| Mar 17, 2014 at 11:59 | history | edited | fgrieu | CC BY-SA 3.0 |
Update with interrogation on why friction can increase the spin rate, and question 2
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| Mar 16, 2014 at 21:17 | comment | added | Renae Lider | @fgrieu friction slows down things and tries to speed them up in the other direction. If we apply friction to a body, it accelerates. This is how we could walk, vehicles could move and in this case the ring could rotate. In fact, there isn't much difference between this case and simply rotating a wheel by rubbing on it. Frictional force did the work in all these cases; not your body, not the car's engine; and not the wrist. Direction is important in determining which force did which work. | |
| Mar 16, 2014 at 17:58 | comment | added | tpg2114 | @fgrieu Friction doesn't always slow motion. Consider a piece of paper at rest on a table. You place your hand on it and pull it parallel to the table -- friction is what accelerated the paper. Friction serves to equalize velocity differences, so one body speeds up and the other slows down. | |
| Mar 16, 2014 at 17:54 | history | edited | Qmechanic♦ | CC BY-SA 3.0 |
edited tags; edited title
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| Mar 16, 2014 at 17:40 | history | edited | fgrieu | CC BY-SA 3.0 |
Fix typo
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| Mar 16, 2014 at 17:38 | comment | added | fgrieu | @user3058846: but usually, friction tends to slow motion, be it linear or rotational. If friction plays a role in the rev up (and I'm ready to believe that), it must be by transferring a torque to the rotor. | |
| Mar 16, 2014 at 16:34 | comment | added | Renae Lider |
It says in the Wikipedia article if the torque is large enough, the friction between the axle and the surface of the groove will speed up the rotation.
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| Mar 16, 2014 at 15:21 | history | asked | fgrieu | CC BY-SA 3.0 |