226: Swingset

Explain xkcd: It's 'cause you're dumb.
Revision as of 06:12, 18 October 2013 by 50.151.2.168 (talk) (Transcript)
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Swingset
Someone bring me a pocket fan so I can drift around the yard.
Title text: Someone bring me a pocket fan so I can drift around the yard.

Explanation

When on a swing, there is a moment between swinging forwards/backwards and falling back down again where the force of gravity stops the acceleration of the swing. In this moment, you remain almost stationary at the peak of your swing and on a perfect swing (i.e. one with no friction or air resistance) you would achieve weightlessness.

Cueball is told this fact by an unknown woman and then he imagines that at the peak of the swing you become permanently weightless and able to float above the ground without any support.

On the title text he asks for a pocket fan, believing he could fly around the garden using this small device.

Transcript

[Woman talking to Cueball on swing-set.]
Woman: You know, at the peak of a big swing, you become weightless.
[Thought bubble from Cueball.]
[Cueball swings higher and higher. At the peak of a big swing he shoves off the swing. Cueball remains hovering in the air.]
Cueball: Hey guys. Come check this out.


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Discussion

A glass with water can be momentarily inverted at this moment and the water will not leave the glass!--DrMath 08:56, 16 November 2013 (UTC)

Isn't the point about illustrating that you do in fact have weight even in instences that are written off as weightless? In space you just happen to be falling at the same velocity of your surroundings, maintaining orbit simply by moving fast enough to miss the Earth. On top of which, in a low enough orbit g is still close to 9.8 m/s^2 if only because altitude is insignificant compared to the radius of the Earth.--Passing Stranger 14:10 August 2014 (UTC)

No, you don't have weight in some instances. Weight is dependent upon gravity, so in deep space with no planets or stars close enough to matter you would be weightless. Mass, on the other hand... 173.245.50.154 01:46, 10 January 2015 (UTC)
He was talking about orbit around a body, where in one sense you still have real weight. The bureaucrats on the ISS have nearly earth-normal weight, being only what, five percent farther from the center of the earth's mass? That weight is simply hidden by the fact that everything else around it has the same relative velocity, all of it falling at the earth and eternally missing, thanks to its forward velocity. I miss Douglas Adams. —Kazvorpal (talk) 01:48, 22 October 2019 (UTC)

The woman appears to be his mother. -- 173.245.52.173 (talk) (please sign your comments with ~~~~)

Weight is actually a description of reaction force; if you're in free fall, and therefore not being pushed on by the floor or pulled on by a rope, you are weightless. If you are being swung on a rope, the direction of your "weight" is constantly changing. This might seem arbitrary, but it avoids things like everyone on a rotating space station being considered "weightless" due to the lack of gravity; a closed physical system can't tell the difference between gravity and uniform acceleration. 108.162.238.159 08:51, 13 May 2015 (UTC)

When I'm alone in elevators, I'll sometimes jump right before the elevator stars to descend. Because I have to fall a longer distance than I jumped, it tricks my brain into feeling a moment of weightlessness more than what I feel at my apogee. I also sometimes like to float underwater for long periods of time, pretending I'm on the ISS. Unfortunately I'm fucking terrified of deep water, and due to my lack of water-based activity, I've quite declined in my ability to hold my breath underwater. I used to be able to do it for at least a minute to a minute and a half when I was 12. I used to either pretend I was Neo, or pretend I was on the ISS or generically in space. Never both, though. Now I can hardly do 20 seconds. Now that I really want to start swimming again, I can't. I grew up with a pool I hardly used, and now I'm in college, and all of our pools are lap-based. i.e. I can't hog 25sqft of space to just be all floaty in. I'd have to take up an entire lane, which I don't want to do. So the only way I'd really be able to experience this is if I scuba dived. Maybe I should do that again. It's the closest, for now, I'll ever get to feeling like I'm in space. Maybe later I can afford a Zero G flight. Maybe later I can do some space tourism stuff. Maybe later I'll be an actual astronaut. Only I'm two inches too short, for now, apparently -3- International Space Station (talk) 09:21, 27 October 2015 (UTC)