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舊 2015-05-03, 02:26 PM   #21
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
預設 回覆: COM

The first version of my definition of COM : "In physics, the center of mass is a point in space where the weighted relative position of the distributed mass sums to zero."

So turned out it is too technical for someone to understand. I already answered it is a weighted function and in this "weight function" calculation, the influence is the mass. Again, that's still too technical. Okay, okay, let's put it in a even less technical way then.

If you glue two balls (ball A and ball B, each has perfectly even mass density) with same radius (radius = r) together and create one object. I call this object has 2 distributed mass located, each located at the center of ball A and B.

1) If the mass of ball A and B are exactly equal. (note: I didn't say "weight" the noun, I said "mass"). Now both ball has the equal amount of influence (same mass) in the calculation. The COM of this glued object is located exactly half way between the center of Ball A and Ball B. This is where the sum of "relative position of ball center A" and "relative position of ball center B" under equal influence (same mass) equal to zero.

2) if the mass of ball A is twice of ball B (note: I didn't say "weight" the noun, I said "mass"). In the same calculation of COM, ball A will have twice the influence compare to ball B (mass of A is 2 times of mass of B). The COM of this glued object is located in the line connecting ball center A and B, but closer to center of ball A. It is located at along the line jointing the center of ball A and B with 2/3 r (radius = r) away from ball A center. It is also 4/3 r away from ball B center on the exact opposite direction.

At this COM location:
1) relative position of ball A center is 2/3 r
2) relative position of ball B center is -4/3 r
3) influence of ball A is 2
4) influence of ball B is 1

"Weighted sum" of the relative position
= relative position of ball A * influence of ball A + relative position of ball B * influence of ball B
= 2/3 r * 2 + (-4/3 r) * 1
= 4/3 r - 4/3 r
= 0

[Nowhere above involves any gravity, force, etc. Just mass in space.]

[I didn't said anything like put the “weight” into the “mass”. I don't know how one could create that term and got confused. I cannot answer this one question at all.]

[I agree with “Arithmetic” is only dealing with the techniques of the calculation. Weighted sum, weighted average is just like +, -, *, /. It is a technique of calculation. There is nothing special about it and it is just another "arithmetic". Everything could make use of this kind of calculation. It is wrong for you to say it used by statistic alone. Physics calculation use all kinds of arithmetic in calculation. Weighted average for complex case in COM calculation, like uneven density or odd shaped object needs, to use integration. Is calculating an integral considered as a “math” by “pure” mathematician?]

[Again, I'm 100% sure what's I'm talking about here and that's the COM meaning used by most people in this world. If you don't like it, you are welcome to prove me wrong.]

[There is nothing wrong for me to say COM = Center of Gravity if it is under an uniform gravity field. Is there anything wrong to say the "length of a rod" is equal to "the height of the rod end when you place the other end vertically on the floor"? When there is no "floor" around, the second part of the measurement is no longer valid. However, that doesn't mean the rod has no length. The rod length doesn't change at all, whether or not there is a floor around. The same for COM, COM doesn't change location whether gravity is involved or not since gravity is not being involved in my definition of COM.]

此篇文章於 2015-05-03 02:30 PM 被 B2L2 編輯。
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舊 2015-05-03, 02:40 PM   #22
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
預設 回覆: COM

Okay, let see why high jumper "move" his Center of Mass outside of his body to obtain good results:

An athlete uses physics to shatter world records - Asaf Bar-Yosef - YouTube


It isn't me who proved you wrong. Mr Dick Fosbury did.
B2L2 目前離線   回覆時引用此篇文章
舊 2015-05-03, 11:01 PM   #23
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
The first version of my definition of COM : "In physics, the center of mass is a point in space where the weighted relative position of the distributed mass sums to zero."

So turned out it is too technical for someone to understand. I already answered it is a weighted function and in this "weight function" calculation, the influence is the mass. Again, that's still too technical. Okay, okay, let's put it in a even less technical way then.
Or only you “一知半解”?

引用:
If you glue two balls (ball A and ball B, each has perfectly even mass density) with same radius (radius = r) together and create one object. I call this object has 2 distributed mass located, each located at the center of ball A and B.

1) If the mass of ball A and B are exactly equal. (note: I didn't say "weight" the noun, I said "mass"). Now both ball has the equal amount of influence (same mass) in the calculation. The COM of this glued object is located exactly half way between the center of Ball A and Ball B. This is where the sum of "relative position of ball center A" and "relative position of ball center B" under equal influence (same mass) equal to zero.

2) if the mass of ball A is twice of ball B (note: I didn't say "weight" the noun, I said "mass"). In the same calculation of COM, ball A will have twice the influence compare to ball B (mass of A is 2 times of mass of B). The COM of this glued object is located in the line connecting ball center A and B, but closer to center of ball A. It is located at along the line jointing the center of ball A and B with 2/3 r (radius = r) away from ball A center. It is also 4/3 r away from ball B center on the exact opposite direction.

At this COM location:
1) relative position of ball A center is 2/3 r
2) relative position of ball B center is -4/3 r
3) influence of ball A is 2
4) influence of ball B is 1

"Weighted sum" of the relative position
= relative position of ball A * influence of ball A + relative position of ball B * influence of ball B
= 2/3 r * 2 + (-4/3 r) * 1
= 4/3 r - 4/3 r
= 0

[Nowhere above involves any gravity, force, etc. Just mass in space.]
Not bad, as least you have learned to search the ‘net to do some “東抄抄西抄抄”, that's “some” study, at least not as arrogant as before, “有進步”‧Nevertheless, what you talk about is the “geometry” property of an object, no need to get involved with “gravity.”

引用:
[I didn't said anything like put the “weight” into the “mass”. I don't know how one could create that term and got confused. I cannot answer this one question at all.]
Neverthelss, what you don't know is, in physics, the “force”/gravity, when in action, is considered only acted at the “centroid,”which is called “center of gravity,” or “center of mass,” even by your most reliable source, Wikipedia,

“In mathematics and physics, the centroid or geometric center of a two-dimensional region is the arithmetic mean ("average") position of all the points in the shape. The definition extends to any object in n-dimensional space: its centroid is the mean position of all the points in all of the coordinate directions. Informally, it is the point at which a cardboard cut-out of the region could be perfectly balanced on the tip of a pencil, assuming uniform density and a uniform gravitational field.
While in geometry the term barycenter is a synonym for "centroid", in physics "barycenter" may also mean the physical center of mass or the center of gravity, depending on the context. The center of mass (and center of gravity in a uniform gravitational field) is the arithmetic mean of all points weighted by the local density or specific weight. If a physical object has uniform density, then its center of mass is the same as the centroid of its shape.
In geography, the centroid of a radial projection of a region of the Earth's surface to sea level is known as the region's geographical center.”

http://en.wikipedia.org/wiki/Centroid


引用:
[I agree with “Arithmetic” is only dealing with the techniques of the calculation. Weighted sum, weighted average is just like +, -, *, /. It is a technique of calculation. There is nothing special about it and it is just another "arithmetic". Everything could make use of this kind of calculation. It is wrong for you to say it used by statistic alone. Physics calculation use all kinds of arithmetic in calculation. Weighted average for complex case in COM calculation, like uneven density or odd shaped object needs, to use integration. Is calculating an integral considered as a “math” by “pure” mathematician?]
“Arithmetic” is only dealing mechanical part of calculation. Nevertheless, how to interpreter the result of calculation is “Math,” so talk about “functions,” in your case, “weighted function” is “Math,” you are confused about Math with arithemetic.

引用:
[Again, I'm 100% sure what's I'm talking about here and that's the COM meaning used by most people in this world. If you don't like it, you are welcome to prove me wrong.]
I have already proved you are wrong in previous posts and in this post as well. If you are confused or don’t under stand, read them again, good for you.

引用:
[There is nothing wrong for me to say COM = Center of Gravity if it is under an uniform gravity field. Is there anything wrong to say the "length of a rod" is equal to "the height of the rod end when you place the other end vertically on the floor"? When there is no "floor" around, the second part of the measurement is no longer valid. However, that doesn't mean the rod has no length. The rod length doesn't change at all, whether or not there is a floor around. The same for COM, COM doesn't change location whether gravity is involved or not since gravity is not being involved in my definition of COM.]
Nothing wrong with COM=CG, (and that was my answer,) but you didn't say that, you shameless liar.

“No, you said COM has nothing to do with gravity, even use the word "again," you liar.

“Again, COM has nothing to do with gravity or force. It is mass only. Even in 0-G environment, an object still have COM.”

http://www.goski.com.tw/forum/showpo...4&postcount=14

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-03, 11:26 PM   #24
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
Okay, let see why high jumper "move" his Center of Mass outside of his body to obtain good results:

An athlete uses physics to shatter world records - Asaf Bar-Yosef - YouTube

It isn't me who proved you wrong. Mr Dick Fosbury did.
No, he may have his interpretation, but he didn't “prove” that I am wrong. The point where he pointed out as COM outside the body is not outside the body, as the body has already “wrap around” the COM point. And what make you think the position of that point is correct? It works equally well if we move that point up to touch the body. And on the high jump one, the COM point is not below the bar, but on top of the body "arc" approximately at the where “丹田” is, ~@2:47. So, it is his “drawing” wrong.

An athlete uses physics to shatter world records - Asaf Bar-Yosef - YouTube



:)
IS

此篇文章於 2015-05-04 12:47 AM 被 taichiskiing 編輯。
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舊 2015-05-05, 03:25 PM   #25
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
預設 回覆: COM

引用:
作者: taichiskiing 查看文章
what you talk about is the “geometry” property of an object, no need to get involved with “gravity.”
Again, one more time, my definition of COM does not involve any gravity/force, etc. Therefore, it still exists with or without gravity. I wouldn't object if you said it is the "geometry" property of an object which doesn't involve gravity.

Your definition of COM, you said it doesn't exist under 0G. This is WRONG.

引用:
作者: taichiskiing 查看文章
Neverthelss, what you don't know is, in physics, the “force”/gravity, when in action, is considered only acted at the “centroid,”which is called “center of gravity,” or “center of mass,” even by your most reliable source, Wikipedia,
You sure you understand what this Wiki page said. It also used the name "weighted". Did you said it is a statistic term that you don't know about? Centroid, why you like to bring in another term into discussion?

WRONG statement that you made. If I have to correct your statement, I could said "in physics, under a uniform force/gravity field, one could consider it only acts at the centroid/center of mass/center of gravity".

This statement said there location is the same under the condition of a uniform force/gravity field. In the Wiki page, it has been repeated a number of time. Why do you think they have to repeat this again and again?

The fact is when under a "non-uniform" force/gravity field, the COM location isn't equal to CG. If you want to find out the COM and CG of a really long rod placed vertical on ground, the two position are NOT the same. Do you know why? Gravity is always lower at higher elevation. CG is always a little bit lower than COM if an object is placed on Earth. Reason? The lower part of the object experience a higher force compare to the higher part of the object.

Yes, if we are talking a human height object, the different of G could be consider really really small since the height different is too small. Mathematically they aren't the same on planet Earth, they are only very close to each other.

I asked about COM of solar system. You said you know the answer, but I really doubt that is correct given all the wrong understand you have. Mind to give out the answer so that I could prove it wrong?

引用:
作者: taichiskiing 查看文章
“Arithmetic” is only dealing mechanical part of calculation. Nevertheless, how to interpreter the result of calculation is “Math,” so talk about “functions,” in your case, “weighted function” is “Math,” you are confused about Math with arithemetic.
Okay, if “weighted function” is “Math”. Then why you said you have a math degree and you know nothing about it?

引用:
作者: taichiskiing 查看文章
I have already proved you are wrong in previous posts and in this post as well. If you are confused or don’t under stand, read them again, good for you.
You never proved me wrong other than "saying" I'm wrong. I said you could try to prove me wrong with support. Where is the support? The Wiki page of Centroid even say things that proved I'm correct.

引用:
作者: taichiskiing 查看文章
Nothing wrong with COM=CG, (and that was my answer,) but you didn't say that, you shameless liar.

“No, you said COM has nothing to do with gravity, even use the word "again," you liar.

“Again, COM has nothing to do with gravity or force. It is mass only. Even in 0-G environment, an object still have COM.”
What did I lie? If you want me to say it one more time, COM has nothing to do with gravity or force. It is mass only. Even in 0-G environment, an object still have COM. And I could add one more line. COM not equal to CG in every conditions. They are at the same location only under a uniform gravity field.

---------------------
http://www.differencebetween.com/dif...enter-of-mass/

Quote: "Center of mass is a fixed property which is the average location of the mass of the body. It has nothing to do with gravity."

Oh, yes, it even use the same wording as mine : "It has nothing to do with gravity."

此篇文章於 2015-05-05 03:43 PM 被 B2L2 編輯。
B2L2 目前離線   回覆時引用此篇文章
舊 2015-05-05, 03:38 PM   #26
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
預設 回覆: COM

引用:
作者: taichiskiing 查看文章
No, he may have his interpretation, but he didn't “prove” that I am wrong. The point where he pointed out as COM outside the body is not outside the body, as the body has already “wrap around” the COM point. And what make you think the position of that point is correct? It works equally well if we move that point up to touch the body. And on the high jump one, the COM point is not below the bar, but on top of the body "arc" approximately at the where “丹田” is, ~@2:47. So, it is his “drawing” wrong.

An athlete uses physics to shatter world records - Asaf Bar-Yosef - YouTube
What make you think you're right and all others are wrong? Prove? Could you provide at least one technical document to prove you're correct? Could you provide at least one human that agree with your thinking?

From now until you could provide that prove, I would "say" you're wrong.

[You claimed the COM is located at the point inside the body closest to the point in the video. Could you explain under which Physics rule that Mr. Dick Fosbury could jump half a meter higher with this style?? Does Mr. Dick Fosbury has a body thickness of 0.5 meter? If not, what energy empower Mr. Dick Fosbury to jump so much higher? Could you explain how Mr. Dick Fosbury could utilize the “imbalance” property of COM (which you claim still located inside his body) to achieve this 0.5 meter gain by using this style of jump only?]
B2L2 目前離線   回覆時引用此篇文章
舊 2015-05-05, 11:13 PM   #27
pku
滑雪瘋7級
 
註冊日期: 2010-05-30
文章: 3,646
預設 回覆: COM

引用:
作者: B2L2 查看文章
What make you think you're right and all others are wrong? Prove? Could you provide at least one technical document to prove you're correct? Could you provide at least one human that agree with your thinking?

From now until you could provide that prove, I would "say" you're wrong.

[You claimed the COM is located at the point inside the body closest to the point in the video. Could you explain under which Physics rule that Mr. Dick Fosbury could jump half a meter higher with this style?? Does Mr. Dick Fosbury has a body thickness of 0.5 meter? If not, what energy empower Mr. Dick Fosbury to jump so much higher? Could you explain how Mr. Dick Fosbury could utilize the “imbalance” property of COM (which you claim still located inside his body) to achieve this 0.5 meter gain by using this style of jump only?]

今次偽太極又可能冇言以對,又走佬一段時間。
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舊 2015-05-06, 02:13 AM   #28
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
Again, one more time, my definition of COM does not involve any gravity/force, etc. Therefore, it still exists with or without gravity. I wouldn't object if you said it is the "geometry" property of an object which doesn't involve gravity.

Your definition of COM, you said it doesn't exist under 0G. This is WRONG.
Whether or not it is “wrong” is depended on what you mean by “center,” in an object where every point is the same as any other point, there is no “center.” Let me put it this way, in regarding of talking about “circular motions,” which is the most “motion” in skiing, on this earth, as stated in PHYSICS, as the gravity only acts on CG, using the term COM is [self-]confusing, and is not “meaningful.”So, in general physics discussion, the terms COM and CG/COG are used synonymously.

引用:
You sure you understand what this Wiki page said. It also used the name "weighted". Did you said it is a statistic term that you don't know about? Centroid, why you like to bring in another term into discussion?
Yes, “weighted” is an ENGLISH term, and statistic is using “ENGLISH” to express its idea. I know better “statistic” than you do, even I haven't taken any classes. “Centroid” is a “BASIC” property of this physical world, it is not a new term but a “Math” knowledge that you don't know. Did say that you lack of math training.

引用:
WRONG statement that you made. If I have to correct your statement, I could said "in physics, under a uniform force/gravity field, one could consider it only acts at the centroid/center of mass/center of gravity".
There's nothing to correct, what you said is only copy my idea. And that is not even my idea but common PHYSICS practice, the “force,” any force, is considered acting only on “centroid,” do you know what that is? Don't know? “Google” it, don't be so arrogant.

引用:
This statement said there location is the same under the condition of a uniform force/gravity field. In the Wiki page, it has been repeated a number of time. Why do you think they have to repeat this again and again?
“Uniform force/gravity field” is an “idealized” condition, easy for consideration and calculation, but the “real” world is seldom ideal, so the “uniform” is an extra/多餘的requirement, only for theoretical study. Even non-uniform force/gravity works the same way uniform force/gravity, more or less.

引用:
The fact is when under a "non-uniform" force/gravity field, the COM location isn't equal to CG. If you want to find out the COM and CG of a really long rod placed vertical on ground, the two position are NOT the same. Do you know why? Gravity is always lower at higher elevation. CG is always a little bit lower than COM if an object is placed on Earth. Reason? The lower part of the object experience a higher force compare to the higher part of the object.

Yes, if we are talking a human height object, the different of G could be consider really really small since the height different is too small. Mathematically they aren't the same on planet Earth, they are only very close to each other.
That's another thing that you don't know about “scientific disciplines.” Math is dealing with “absolute,” and physics is dealing with “approximate,” and engineering “practical.” So, given a theorem generates 10 samples/data, in math, one sample/data wrong, the whole theorem is wrong; in physics, physicists just throw out the wrong one, and refer it as “exception,” and the theorem may require further refinement, but meanwhile the theorem is “valid,” and engineers take “average” to be practical, they may not care what is the theorem or what it says. All of them are science, but different disciplines, and you know none of them.

引用:
I asked about COM of solar system. You said you know the answer, but I really doubt that is correct given all the wrong understand you have. Mind to give out the answer so that I could prove it wrong?
I have the same idea, since you haven't answer any of my questions, and I have proved all your explanations on this subject are wrong. Never mind, we're just going to see you wiggle again. COM of the solar system is at CG of the solar system, of course.

引用:
Okay, if “weighted function” is “Math”. Then why you said you have a math degree and you know nothing about it?
I didn't take any “statistic classes,” and that is to say, a math degree does NOT require knowing “weighted function.” But now, I do know better statistic than you do.

引用:
You never proved me wrong other than "saying" I'm wrong. I said you could try to prove me wrong with support. Where is the support? The Wiki page of Centroid even say things that proved I'm correct.
You don't know what a proof is, then you wouldn't know that you have been proved wrong. According to my proofs, you haven't been right yet.

引用:
What did I lie? If you want me to say it one more time, COM has nothing to do with gravity or force. It is mass only. Even in 0-G environment, an object still have COM. And I could add one more line. COM not equal to CG in every conditions. They are at the same location only under a uniform gravity field.
Given the argument above, COM is an unnecessary term.

引用:
---------------------
http://www.differencebetween.com/dif...enter-of-mass/

Quote: "Center of mass is a fixed property which is the average location of the mass of the body. It has nothing to do with gravity."

Oh, yes, it even use the same wording as mine : "It has nothing to do with gravity."
Apparently that you have googled the question, did you find both answers? I'm stick with “COM is an extra/多餘的” camp.

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-06, 02:20 AM   #29
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
What make you think you're right and all others are wrong? Prove? Could you provide at least one technical document to prove you're correct? Could you provide at least one human that agree with your thinking?
Logic. Logic. Logic.

Flatboarding: A lesson on Line Skiing, Direct to Parallel, Wedeln, and Slipping Turns - YouTube



引用:
From now until you could provide that prove, I would "say" you're wrong.
Whatever, your “無恥鐵齒” only cheat yourself.

引用:
[You claimed the COM is located at the point inside the body closest to the point in the video. Could you explain under which Physics rule that Mr. Dick Fosbury could jump half a meter higher with this style?? Does Mr. Dick Fosbury has a body thickness of 0.5 meter? If not, what energy empower Mr. Dick Fosbury to jump so much higher? Could you explain how Mr. Dick Fosbury could utilize the “imbalance” property of COM (which you claim still located inside his body) to achieve this 0.5 meter gain by using this style of jump only?]
On second thought, I'll scratch the COM totally, and now I claim the position of the CG doesn't change (remains at the same place) with the “body” change shapes. What is changed is only the “balance point.”When the high jumper running, his “balance point” is on his feet, after the jump, through his body structure (muscles, skins and bones), he have moved the balance point to the back shoulder, which is “imbalance,” so it “falls” to the ground and carries the CG/body with it, and in this explanation there's no need for a “COM.”“COM”is an extra term/多餘的‧


:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-06, 04:24 AM   #30
pku
滑雪瘋7級
 
註冊日期: 2010-05-30
文章: 3,646
預設 回覆: COM

引用:
作者: taichiskiing 查看文章
Logic. Logic. Logic.

Flatboarding: A lesson on Line Skiing, Direct to Parallel, Wedeln, and Slipping Turns - YouTube




Whatever, your “無恥鐵齒” only cheat yourself.



On second thought, I'll scratch the COM totally, and now I claim the position of the CG doesn't change (remains at the same place) with the “body” change shapes. What is changed is only the “balance point.”When the high jumper running, his “balance point” is on his feet, after the jump, through his body structure (muscles, skins and bones), he have moved the balance point to the back shoulder, which is “imbalance,” so it “falls” to the ground and carries the CG/body with it, and in this explanation there's no need for a “COM.”“COM”is an extra term/多餘的‧


:)
IS
Logic, 那橫滑 Zig Zag turn 怎會 effective, 你這樣滑怎跟人家比,但你死囗說人家沒有特別,你自己的滑法是高水準,你看你的腳經常分開,速度快了便要用橫滑和 side slipping 來減速, energy loss 得那麼厲害,


Taichi Skiing/Flatboarding: bumps 1 - YouTube



Ski Schoolin! - Skiing Bigger Turns In Bumps - YouTube



Skiing on slightly melted frozen bumps 2013 - YouTube


此篇文章於 2015-05-06 04:45 AM 被 pku 編輯。
pku 目前離線   回覆時引用此篇文章
舊 2015-05-06, 07:08 AM   #31
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: pku 查看文章
Logic, 那橫滑 Zig Zag turn 怎會 effective, 你這樣滑怎跟人家比,但你死囗說人家沒有特別,你自己的滑法是高水準,你看你的腳經常分開,速度快了便要用橫滑和 side slipping 來減速, energy loss 得那麼厲害,
你的“短見”‧

Taichi Skiing/Flatboarding: bumps 1 - YouTube



Ski Schoolin! - Skiing Bigger Turns In Bumps - YouTube



Skiing on slightly melted frozen bumps 2013 - YouTube



應時應景,我的滑雪是“活”的‧

Taichi Skiing/Line-skiing: powder gully skiing - YouTube



:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-06, 10:42 AM   #32
pku
滑雪瘋7級
 
註冊日期: 2010-05-30
文章: 3,646
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事實就是 energy lost 越多,速度越減,你的 kinetic energy 不是這樣嗎,

每個人滑雪都是活的,低手到陡坡自然要橫滑減速, Side slip 當然不能避免,不過你 side slip 也控制得不大好,所以滑橫仍是你核心技術,什麼腳隨意轉,還是留在好雪平坦的 trail 做,什麼合附物理,數學,講出來做不到,人家也不能拿你打靶

什麼 line skiing , 見歩行歩,陡時橫滑,平坦時轉快些,一年滑一佰日,滑了那麼多年仍滑成這樣,簡直丟人現眼

此篇文章於 2015-05-06 12:50 PM 被 pku 編輯。
pku 目前離線   回覆時引用此篇文章
舊 2015-05-06, 01:17 PM   #33
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
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From now until you could provide that prove, I would "say" you're wrong.
B2L2 目前離線   回覆時引用此篇文章
舊 2015-05-06, 09:07 PM   #34
pku
滑雪瘋7級
 
註冊日期: 2010-05-30
文章: 3,646
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引用:
作者: B2L2 查看文章
From now until you could provide that prove, I would "say" you're wrong.
僞太極講什麼講不過都要死辯說自己是對,說人家不錯丶這是他幾十年在論壇的作風,

不過他不知道經常詆毀的 whistler group 是人材濟濟,我剛 confirm with Derek, he got two master degree, one in information system, one in Physic. 而且他也是台灣人,也是 CSIA 2 ,更是 CASI 2


不過叫他來對付偽太極,偽太極隨時躱回他的狐狸洞,我便沒有人給我駡
pku 目前離線   回覆時引用此篇文章
舊 2015-05-07, 01:01 AM   #35
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: pku 查看文章
事實就是 energy lost 越多,速度越減,你的 kinetic energy 不是這樣嗎,
是,也不是,地力老人的energy是源源不絕的,就看你懂不懂得,會不會用而已。

引用:
每個人滑雪都是活的,低手到陡坡自然要橫滑減速, Side slip 當然不能避免,不過你 side slip 也控制得不大好,所以滑橫仍是你核心技術,什麼腳隨意轉,還是留在好雪平坦的 trail 做,什麼合附物理,數學,講出來做不到,人家也不能拿你打靶
不是,你只有一種滑法,你到那滑也都是那個滑法,合乎你技術的地形/饅頭坡你滑的順,不合你技術的地形/樹林、半管溝等你就不行了,而你的“轉彎滑雪”的轉彎的弧度/turn shape也只有一種,所以不規則的地形你也不能滑,所以是“死”的‧

Flatboarding: off-piste skiing, Castle Creek, Sierra-at-Tahoe - YouTube



引用:
什麼 line skiing , 見歩行歩,陡時橫滑,平坦時轉快些,一年滑一佰日,滑了那麼多年仍滑成這樣,簡直丟人現眼
Line Skiing 不用雪杖滑起雪來像飛滑翔機一樣,轉化“位能”為“動能”,坐/騎/借地力而享受滑雪的樂趣,也可以假想一下飛行(滑雪減少了大部份地面摩擦力,可以想像是變相的飛行)‧你所謂的“橫滑”是保持“位能”,“直衝”是最有效的“轉化“位能”為“動能””,所以快,而“橫滑”跟“直衝”並不互補,要協調它們就是“技術”,遠比你只“想”滑快的turn skiing“有深度”,“高級”‧

Taichi Skiing/Flatboarding: flatskiing - YouTube



你是連我“這樣”簡單的滑雪都看不懂,“丟人現眼”你自己。

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-07, 01:03 AM   #36
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
From now until you could provide that prove, I would "say" you're wrong.
小知小技小人的“無恥鐵齒”, thanks for proving it.

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-07, 01:06 AM   #37
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: pku 查看文章
僞太極講什麼講不過都要死辯說自己是對,說人家不錯丶這是他幾十年在論壇的作風,
“無恥鐵齒”,你說的是你們whistler group的作風,我在這裡“証明”之。

引用:
不過他不知道經常詆毀的 whistler group 是人材濟濟,我剛 confirm with Derek, he got two master degree, one in information system, one in Physic. 而且他也是台灣人,也是 CSIA 2 ,更是 CASI 2


不過叫他來對付偽太極,偽太極隨時躱回他的狐狸洞,我便沒有人給我駡
他要是真是 master degree in physics, 他是不會來的—羞與你們whistler group為伍討論物理—就是他來,他也辯不倒我‧不對的不說,所以我說的總是對的,就是那麼簡單‧看來你頭皮也是越來越厚了。

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
舊 2015-05-07, 11:02 AM   #38
B2L2
滑雪瘋3級
 
註冊日期: 2011-03-04
文章: 346
預設 回覆: COM

[quote=taichiskiing;30220]小知小技小人的“無恥鐵齒”, thanks for proving it./QUOTE]

Other than BS-ing everyday, why don't just go to find one article or one person who agree with your theory. How about go ask your old professor who taught you to prove you are right?

I don't believe there isn't a single article exist in this world that describe a simple theory.

My statement remain the same. Until you could find a prove, your theory remain wrong as I call.
B2L2 目前離線   回覆時引用此篇文章
舊 2015-05-07, 12:17 PM   #39
pku
滑雪瘋7級
 
註冊日期: 2010-05-30
文章: 3,646
預設 回覆: COM

引用:
作者: taichiskiing 查看文章
是,也不是,地力老人的energy是源源不絕的,就看你懂不懂得,會不會用而已。



不是,你只有一種滑法,你到那滑也都是那個滑法,合乎你技術的地形/饅頭坡你滑的順,不合你技術的地形/樹林、半管溝等你就不行了,而你的“轉彎滑雪”的轉彎的弧度/turn shape也只有一種,所以不規則的地形你也不能滑,所以是“死”的‧

Flatboarding: off-piste skiing, Castle Creek, Sierra-at-Tahoe - YouTube




Line Skiing 不用雪杖滑起雪來像飛滑翔機一樣,轉化“位能”為“動能”,坐/騎/借地力而享受滑雪的樂趣,也可以假想一下飛行(滑雪減少了大部份地面摩擦力,可以想像是變相的飛行)‧你所謂的“橫滑”是保持“位能”,“直衝”是最有效的“轉化“位能”為“動能””,所以快,而“橫滑”跟“直衝”並不互補,要協調它們就是“技術”,遠比你只“想”滑快的turn skiing“有深度”,“高級”‧

Taichi Skiing/Flatboarding: flatskiing - YouTube


你是連我“這樣”簡單的滑雪都看不懂,“丟人現眼”你自己。

:)
IS
今次你說對了,要高水準滑到陡一點的坡,是需要一定的體力,而且你技術有限,所以要用低級滑雪技術樣energy 流失多點,你受的力才可減低,你才有 energy 滑下來,不過源源不絕是你的囗水,死剰把口是真的,不過滑出來的樣子就慘不忍睹

你技術那麼低,你帶雪杖對你是一種負累,如果滑翔機像你滑陡坡那樣,幾秒就墮機,無恥老人,你省點吧

你滑雪那麼簡單,一看就明,晨運亞伯遊山,你不說你是高手,就不會丟人現眼
pku 目前離線   回覆時引用此篇文章
舊 2015-05-08, 01:25 AM   #40
taichiskiing
滑雪瘋7級
 
註冊日期: 2009-02-07
文章: 3,756
預設 回覆: COM

引用:
作者: B2L2 查看文章
引用:
作者: taichiskiing 查看文章
小知小技小人的“無恥鐵齒”, thanks for proving it.
Other than BS-ing everyday, why don't just go to find one article or one person who agree with your theory. How about go ask your old professor who taught you to prove you are right?
“Other than BS-ing everyday” yourself, why don't you disprove my statements, or prove your statements without being debunked? (That's the only scientific way, "stick with math/sci," remember?) You can't, “can't learn, can't grow,” you remain a 小知。

引用:
I don't believe there isn't a single article exist in this world that describe a simple theory.
Double negative, you have lost me, care to rephrase it again?

引用:
My statement remain the same. Until you could find a prove, your theory remain wrong as I call.
“小知小技小人的“無恥鐵齒”, thanks for proving it.”

:)
IS
taichiskiing 目前離線   回覆時引用此篇文章
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