Member of the Month

KilaTsunami
October, 2024

Online

Welcome to the Newschoolers forums! You may read the forums as a guest, however you must be a registered member to post. Register to become a member today!

Physics of a cork?

profile picture
Miomo
Posts: 4302 - Karma: 14,133
Anyone have or know anything about the physics behind a cork? I've always been interested as to how it actually works.
Sep 27 2012 8:44PM
13 0
profile picture
Parks.
Posts: 5612 - Karma: 1,093
off axis spin? like i dont know what you are really asking?
Sep 27 2012 8:45PM
0 0
profile picture
FuckAllOfYou
Posts: 3864 - Karma: 2,518
better question. this one's always tough for me -

what's the difference between a flat and cork...? I've been throwing flats lately and i'm wondering if I'm doing them right...
Sep 27 2012 8:47PM
0 0
profile picture
Kretzschmar
Posts: 6707 - Karma: 98,279
here
/thred
Sep 27 2012 8:49PM
0 0
profile picture
L1FTED
Posts: 220 - Karma: 73
cork is a spin where your head goes below your waist at some point of the rotation. on a horizontal level.  just my 2 cents
Sep 27 2012 8:52PM
0 0
profile picture
Miomo
Posts: 4302 - Karma: 14,133
Eh. I've seen that before, but what I mean is something along the lines of how the different axes interact to create something off-axis.
Sep 27 2012 8:56PM
0 0
profile picture
roddy116
Posts: 10627 - Karma: 7,423
i have always wondered if its more of a backflip spin or a frontfip type spin.
Sep 27 2012 9:00PM
0 0
profile picture
Miomo
Posts: 4302 - Karma: 14,133
It's more backflip because you throw yourself backwards, but when you're more or less parallel to the ground, you're rotating towards the back.
Sep 27 2012 9:04PM
0 0
profile picture
Malcolm
Posts: 15951 - Karma: 9,451
2:10 nailed it
Sep 27 2012 9:44PM
0 0
profile picture
dizzydizzy
Posts: 302 - Karma: 1,031
this. do future spins, get paid.
Sep 27 2012 10:41PM
0 0
profile picture
^nate^
Posts: 1263 - Karma: 560
Take a stroll with me, I think this might be a decent explanation.

The physics of a cork has to deal with the extension of Newton's first law in rotating frames. Newton's first law states, objects in motion tend to stay in motion. If we extend this to a rotating frame, say for example a rotating wheel, it will tend to remain in its axis of rotation, i.e. if you tilt the wheel while it's spinning, you will feel it want to straighten out again. This is how motocross whips work. The rotation of the back wheel helps bring the rider forwards again (as well as body position).

The same phenomenon occurs when you throw yourself corked, but also with the aid of body position, i.e. the position of your center of mass. If we take that out of the logic however, the underlying idea is the same as a motocross whip but in a perpendicular frame. The body rotates about the vertical z-axis while tipping backwards into the y-axis, given the spin is thrown looking into the positive x-axis (just think regular 3D cartesian frame here). The tipped rotation wants to move back towards the "untipped", or upright original frame as the skier keeps spinning. Remember, this is the same as the motocross whip just in a different frame.

For double/triple corks this process occurs multiple times with the aid of holding your body position to cork "again" after coming upright.

Like I said a couple times though, a lot of this is purely dependent on body position and when one "opens" or "closes" their body to change their moment of inertia, but as a whole I'd say the above is significant portion of the "physics" of corking.

Hope that helps.


Sep 28 2012 12:38AM
1 0
profile picture
DIX~
Posts: 4695 - Karma: 6,502
10/10
Sep 28 2012 12:57AM
1 0
profile picture
^nate^
Posts: 1263 - Karma: 560
oops, totally missed that sport science video, but they really didn't answer how corking works, just torque and rotation.

also, I totally overlooked the easiest analogy to extend to the explanation. The dradle is a perfect example of "corking". When it's deflected while rotating, it converses its axis of rotation and returns upright.
Sep 28 2012 12:58AM
1 0
profile picture
^nate^
Posts: 1263 - Karma: 560
conserves* (last sentence)

sorry for triple post.
Sep 28 2012 1:09AM
1 0
profile picture
Kjell
Posts: 434 - Karma: 100
^nate^ scores 100%

If you can't read his essay however here are sparknotes:
When you spin something then tilt it it will try to return to it's original position. (Gyroscope)
With a cork you do a regular spin about a vertical axis then tilt it, this means that the body will try to return to the original vertical position if you just keep spinning.
Doubles/Triples are just the same thing over and over.


Sep 28 2012 7:50AM
1 0
profile picture
deet
Posts: 246 - Karma: 665
1:44 "she"?
Sep 28 2012 9:12AM
0 0
profile picture
ski4fun420
Posts: 902 - Karma: 842
Watch this from sports science: http://espn.go.com/video/clip?id=7506424
Sep 28 2012 9:47AM
0 0
profile picture
Kretzschmar
Posts: 6707 - Karma: 98,279
i posted that clip above...
Sep 28 2012 10:15AM
0 0
profile picture
GKO
Posts: 1467 - Karma: 1,410
threads
Sep 28 2012 3:43PM
0 0
profile picture
jimmydar
Posts: 852 - Karma: 1,628
threads
Sep 28 2012 3:54PM
0 0
profile picture
the.nile
Posts: 580 - Karma: 153
that guy has huge ears
Sep 28 2012 6:34PM
0 0
profile picture
TheQuailman
Posts: 7382 - Karma: 147

If you took any object and threw it in the air you wouldn't be able to make it do a cork rotation.

But our bodies are flexible and we can change our center of gravity mid-air fairly easily.  Aided by the angle of the jump and landing, its pretty easy.  You just throw your torso horizontal as you leave the lip and rotate on that axis and then pick up your head and then shoulders, chest, and torso to 'uncork'.  Forunately ski boots and skis weigh shit load and thus make it easier to 'land on your feet'.

Sep 29 2012 12:16AM
0 0
profile picture
Spiri7o
Posts: 2163 - Karma: 1,100
Pretty much lol
Sep 29 2012 12:17AM
0 0
profile picture
I_Am_Mod
Posts: 13214 - Karma: 3,753
fully torqued dude !

Sep 29 2012 6:18AM
0 0
profile picture
I.B
Posts: 8137 - Karma: 24,352
First thing that came to my mind when they said torque.
Sep 29 2012 12:13PM
0 0
profile picture
schu2122
Posts: 247 - Karma: 24
this
Nov 1 2012 9:26PM
0 0
profile picture
Ali_Dibden
Posts: 1966 - Karma: 1,688
Haha, yes to that vid!
Nov 2 2012 4:43PM
0 0
profile picture
Ski_The_E
Posts: 1036 - Karma: 944
Wrong, thats a d spin cork is just off axis.
Nov 2 2012 5:21PM
0 0
profile picture
Ski_The_E
Posts: 1036 - Karma: 944
Also its more of a backflip, but please realize, corks are not flips. Tons of my non-skiing friends have trouble understanding the concept of any trick that involves going off axis but not straight over flipping.
Nov 2 2012 5:25PM
0 0
profile picture
Stickity
Posts: 7750 - Karma: 769
a perfect flat should be like rotating around while laying on your back without much actual spinning. it should be thrown backwards

a cork, also thrown backwards, is you lean back, spin, and come back to your feet without your feet ever going over your head
Nov 2 2012 6:26PM
0 0
profile picture
Stose
Posts: 7109 - Karma: 4,123
He's asking how you get back on axis
Nov 2 2012 7:00PM
0 0
profile picture
malux94
Posts: 232 - Karma: 25
Does anyone else do tricks with objects? Like I use my iPhone to do any type of trick, from kangs to dub corks and stuff. Anyone?
Nov 2 2012 11:18PM
0 0
profile picture
Ski_The_E
Posts: 1036 - Karma: 944
I prefer gatorade bottles.
Nov 2 2012 11:42PM
0 0
profile picture
whitechocolate
Posts: 582 - Karma: 260
ya usually i use my mac laptop. it has real good spin
Nov 6 2012 3:15AM
0 0
profile picture
LIL-WAT
Posts: 1510 - Karma: 146
i use my goat, he has developed great air awareness
Nov 6 2012 4:53AM
0 0
profile picture
wesley.
Posts: 6483 - Karma: 1,049
you can have more than one "cork" axis. A d spin is just a flippy cork and a flippy d spin will end up like a back full. less flippy back full=cork 7. another way to think of a cork is inverted 180 to misty 5.
Nov 6 2012 9:31AM
0 0
profile picture
phishfood
Posts: 2542 - Karma: 298
This is just wrong...heavier things don't fall faster...
Nov 6 2012 9:43AM
0 0
All times are Eastern (-5)