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| | The momentum of Megan is in fact one order of magnitude smaller than what appeared in above calculation, so the dilation effect is still smaller. | | The momentum of Megan is in fact one order of magnitude smaller than what appeared in above calculation, so the dilation effect is still smaller. |
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| − | http://www.wolframalpha.com/input/?i=moment+of+inertia+of+solid+cylinder+for+a%3D0.25m%2Cmass%3D62kg {{unsigned ip|173.245.50.90}} | + | http://www.wolframalpha.com/input/?i=moment+of+inertia+of+solid+cylinder+for+a%3D0.25m%2Cmass%3D62kg |
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| − | After reading this comics, I got one question. I thought one cant change the total momentum of a closed system of bodies. I mean, from the point of view outside of Earth, she would be spinning, but the momentum which Megan, or whatever her name is, gained in counter-clock-wise direction would also show in Earth clock-wise direction (positively). Basically I am referring to a situation of a man walking on a boat. (the boat moves, the man moves, but the position man-lake is still the same). So I figured it should be in this way. She spins, yeah, but the Earth now spins in opposite direction a little more, so in the end it is still the same.
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| − | Now, she could totally delay time by approaching light speed as she spins, which would be weird though as her head (closer to rotational axis) would have smaller velocity than her hands (and thus faster time flow) resulting in, hmm, her body parts getting lost in time? {{unsigned ip|141.101.97.220}}
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| − | :The total angular momentum cannot be altered from inside the closed system, but it can be distributed differently among the different bodies. This means that the angular speed of the Earth will be actually reduced, but only of a fixed value (proportional to Megan's angular speed) and only as long as Megan spins. It will revert to its original value when Megan stops spinning. [[User:Alexxx|Alexxx]] ([[User talk:Alexxx|talk]]) 23:24, 6 December 2015 (UTC) {{unsigned ip|141.101.104.8}}
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| − | ::The total angular momentum is not changed, but while Megan is spinning the Earth is rotating slower. When she stops spinning, the Earth resumes it's previous spin rate, but not in the same position, and therefore dawn comes later.
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| − | ::You can compare with the man on the boat situation. If a man walks forward in the boat, the boat moves backward; when the man stops, the boat stops, too, but it is not in the same position it was at the beginning.--[[User:Pere prlpz|Pere prlpz]] ([[User talk:Pere prlpz|talk]]) 17:29, 17 December 2015 (UTC)
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| − | Wouldn't she have to be spinning at the Geographic North Pole to have any effect? As it is she's spinning with her axis of rotation at some angle (depending on latitude ) to the Earth's axis of rotation so she's not having much of any effect at all. [[Special:Contributions/173.245.54.190|173.245.54.190]] 10:15, 2 April 2015 (UTC)
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| − | :The effect is stronger in the North Pole, but in temperate latidudes it's still strong. In fact, it's proportional to sine of latitude. Therefore, if the comic is set in Boston (where I think Randall lives), it's just a 33% weaker than in the Pole (sin(42º)=0,67).
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| − | :Furthermore, out of the Pole, Megan's spin will slightly change the Earth's rotation axis, but this will have little effect on the time of dawn.--[[User:Pere prlpz|Pere prlpz]] ([[User talk:Pere prlpz|talk]]) 17:22, 17 December 2015 (UTC)
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| − | Is she spinning counter clockwise when viewed from below or above? (Up spin or down spin?) [[Special:Contributions/108.162.219.188|108.162.219.188]] 06:35, 24 June 2015 (UTC)
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| − | :I'm guessing she's spinning counter-clockwise as viewed from above. (I think that would be up-spin, by the {{w|Right-hand rule#A rotating body|right-hand-rule}}, if that's what you mean.) Assuming she's in the northern hemisphere, if I understand this correctly, as she pushes herself counter-clockwise, her feet exert ''clockwise'' torque on the earth, opposing the earth's ''counter''-clockwise rotation on its axis (as viewed from above the north pole), slowing the earth's rotation slightly, thus "lengthening the night, pushing back the dawn"...by a mere 5.767×10<sup>-24</sup> seconds (according to earlier comments) — I think that's the joke in this comic. -- [[User:Yfmcpxpj|Yfmcpxpj]] ([[User talk:Yfmcpxpj|talk]]) 16:24, 6 December 2019 (UTC)
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| − | I'm no physicist, but the opening paragraph of the explanation seems to be about {{w|Momentum|''linear'' momentum}}, <code>p=mv</code>, whereas I think the comic might be referring to {{w|Angular momentum|''angular'' momentum}}, <code>L=Iω</code>. I wonder if Megan isn't trying to slow the earth's speed around the sun, nor trying to "slow down the rate of time", but is actually trying to "lengthen the night, push back the dawn" (because their time together will end at dawn), by slowing down the earth's rotation on its own axis? -- [[User:Yfmcpxpj|Yfmcpxpj]] ([[User talk:Yfmcpxpj|talk]]) 16:24, 6 December 2019 (UTC)
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