Differences
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| Both sides previous revision Previous revision Next revision | Previous revisionLast revisionBoth sides next revision | ||
| 183_notes:examples:a_yo-yo [2014/10/31 16:28] – pwirving | 183_notes:examples:a_yo-yo [2014/11/06 02:41] – pwirving | ||
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| === Assumptions and Approximations === | === Assumptions and Approximations === | ||
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| + | You are able to maintain constant force when pulling up on yo-yo | ||
| + | |||
| + | Assume no slipping of string around the axle. Spindle turns the same amount as string that has unravelled | ||
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| + | No wobble included | ||
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| + | String has no mass | ||
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| === Lacking === | === Lacking === | ||
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| + | Change in translational kinetic energy of the yo-yo | ||
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| + | Change in the rotational kinetic energy of the yo-yo | ||
| === Representations === | === Representations === | ||
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| Surroundings: | Surroundings: | ||
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| + | {{course_planning: | ||
| b: | b: | ||
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| Surroundings: | Surroundings: | ||
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| + | {{course_planning: | ||
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| + | $\Delta K_{trans}$ = $\int_i^f \vec{F}_{net} \cdot d\vec{r}_{cm}$ | ||
| === Solution === | === Solution === | ||
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| $\Delta K_{trans} = (F - mg)\Delta y_{CM}$ | $\Delta K_{trans} = (F - mg)\Delta y_{CM}$ | ||
| - | $\Delta y_{CM} = -h (from digram)$ | + | $\Delta y_{CM} = -h (from\; digram)$ |
| $\Delta K_{trans} = (F - mg)(-h) = (mg - F)h$ | $\Delta K_{trans} = (F - mg)(-h) = (mg - F)h$ | ||