# center of mass



## wrathfuldeity (Oct 5, 2007)

think of your board as the bottom of a cereal box...keep all your body parts inside the box. and the box does tilt...but generally your body...or really your mass/center of gravity is also tilted/aligned/stacked over the bottom of the cereal box


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## Artu89 (Nov 24, 2010)

so suppose that my inclination during turn is 45 degree (i'm in the "box" so board's angulation is 45 too - center of mass over board) but i angulate the board by ankles by 2 degree. Probably center of mass is not over the board now? I have to increase inclination in this case to return center of mass over the board?  

I know it might be too theoretical but i'm curiouse about it 

Is it possible to be stable in the turn when my mass center isnt over working edge?

And how center of mass is related to centrifugal force?


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## crash77 (Jan 24, 2011)

Uh..umm..:icon_scratch:


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## wrathfuldeity (Oct 5, 2007)

Artu89 said:


> so suppose that my inclination during turn is 45 degree (i'm in the "box" so board's angulation is 45 too - center of mass over board) but i angulate the board by ankles by 2 degree. Probably center of mass is not over the board now? I have to increase inclination in this case to return center of mass over the board?
> 
> I know it might be too theoretical but i'm curiouse about it
> 
> ...


umm...idk...but you also are probably lowering your cog because you are squating instead of standing straight legged....so the relative position or angle to pressure the edge is different. I'd imagine also you are entering and exiting the box and angle differently using cross under turns vs cross over turns and the angle of attacking the snow/fall line is going to be more parallel with the fall line...instead of transversing it.

....its kind of using 4 dimensional space....x, y, z and moving/time/speed instead of your above perspective which seems more 2 dimensional.


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## Donutz (May 12, 2010)

If you draw a line from _your_ center of mass - which is usually just behind the belly button -- through the center of the board, that'll give you the vector at which the board is pushing against the Earth. Assuming you're balanced of course. If you just lean over while standing still, you'll just fall over. The amount of lean should just balance the "centrifugal force" so that you stay on your board through the turn. Angling the board is an additional complication. It doesn't affect center of mass or the angle of the vector, but it does affect whether or not your board is able to hold you in the turn. Put the board too flat and you'll slide out.

Of course there are things you can do to affect your center of mass. For instance, sticking your arms out in front of you will shift your center of mass forward, requiring more lean. Squatting will shift your center of mass back.


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## crash77 (Jan 24, 2011)

This is interesting because I couldn't explain this technically and scientifically speaking if I wanted to, but I can feel everything that is being explained above through the board and my body every time I ride. It's like a conversation of relativity between the two. :blink:


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## Artu89 (Nov 24, 2010)

thx guys for replies 

The last question:

Here:










mass center is over the edge, otherwise it would be wipeout?


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## Vinh (Feb 19, 2013)

He's probably going fast enough so the centrifugal forces outweigh the force of the gravity. (Did this come out right? :laugh: )

It's the same as those MotoGP riders when they're hanging all the way into their turns. One little slip and you're on the ground though.


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## crash77 (Jan 24, 2011)

MotoGP is the shit! Can't wait for this season...Rossi back on a Yami!


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## stillz (Jan 5, 2010)

This guy's momentum vector is balanced over his edge. Centrifugal force doesn't exist, and neither do double fall lines. They are illusions. Anyway...

Inclination is the angle between your weight vector (vertical) and the vector formed by connecting your center of mass to the board. Without the jargon, it means leaning into your turns. You can make heavy use of inclination if the surface is consistent and edgeable (groomers). On ice, moguls, icy moguls, powder, or any variable conditions, inclining your body relative to vertical frequently makes you fall. Angulation is articulating the joints in the body to create edge pressure/edge angle while keeping the body vertical. In the photo, the guy's upper body is nearly vertical. He is using a combination of lots of inclination and lots of angulation. Using angulation allows him to make shorter radius turns, since only his legs (rather than his whole body) need to change their momentum and orientation to the hill to make the board change edges.


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## edlo (Jan 24, 2011)

Artu89 said:


> thx guys for replies
> 
> 
> mass center is over the edge, otherwise it would be wipeout?


No wipeout because f x sin A =mass x gravity . I hope this translates.


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