LynnBlakeGolf Forums - Pivot center

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- Golf By Jeff M (http://www.lynnblakegolf.com/forum/forumdisplay.php?f=152)

- - Pivot center (http://www.lynnblakegolf.com/forum/showthread.php?t=6288)

Quote:

Originally Posted by Jeff (Post 59229)

Yoda - you stated-: "Then again, that's why I've created this Golf By Jeff Forum and given you domain. Here you can pick things apart to your heart's content and enjoy relative freedom from my comment. But, it's also why I've put a 'caveat emptor' sign at the front door and stated that your presence here does not imply endorsement of your opinions by LBG."

I have no problem with that "caveat emptor" sign at the front door. That does not insult me. That simply warns people to be very skeptical of my expressed opinions.

Also, when you state-: "Get your facts right, Jeff, and you'll have no beef from me. Otherwise, I suggest getting fitted for a flak jacket."

That doesn't bother me. You, or anybody else, is free to criticise me as much as they want.

However, I resent the following series of statements-: "Yet, you then totally deep-end and restate to your own end basic laws of physics that have been accepted since the time Isaac Newton wrote his Philosophiæ Naturalis Principia Mathematica (1687). You put up a lot of good stuff, Jeff, but man, you make it difficult to sit idly by as you reinvent concepts that have served mankind well for centuries. --- To me, that's arrogance."

I am obviously not attempting to reinvent Newtonian laws. I may be misunderstanding them, or misrepresenting them - but I am not arrogantly reinventing them. You know that! Also, if I am so obviously wrong, why didn't you bother to show me my errors by means of an explanatory logical argument?

Going back to the orbiting ball example.

Consider this diagram.

The ball is orbiting on the outer circle at a constant speed. The hand is moving along the inner circle. A taut string connects the hand to the orbiting ball.

At ball position X, the hand is slightly ahead of the ball when it is at position A. That means that the hand is pulling the orbiting ball via the taut string. The source of energy in the system is the hand-in-motion.

If the ball moves to position Y, then two forms of energy are required - i) energy to move the ball at a constant speed; ii) energy to move the ball in a circular direction (represented by the red arrows) and that represents energy to provide centripetal acceleration. Where does the energy come from? There is only one rational answer - it comes from the orbiting hand that moves from position A to position B. The taut string is simply an inert "connection" between the hand and the orbiting ball, and it allows hand motion to provide the energy to the orbiting ball, which then i) moves the orbiting ball at a constant speed and ii) it provides the energy to centripetally accelerate the ball so that it continues to move along a circular path. The string is not the source of any energy, or the source of a centripetal force.

If you disagree with my opinion, and you have the "facts", then please provide a counterargument.

Here is composite photo of Tiger Woods and Jamie Sadlowski.

The yellow dotted line shows the direction Tiger's hands and central clubshaft are pointing at when the club moves in the late downswing to impact. They are in a straight line relationship with a straight line drawn through the clubhead's sweetspot - the red dotted line. That makes biomechanical sense. Look at where Jamie Sadlowski's hands are pointing (yellow dotted line). They are not pointing at the clubhead's sweetspot. How does one explain that fact? Either we are dealing with an additional "force" (or factor) that has caused the clubhead and peripheral end of the clubshaft to be deflected forward (relative to the hand position), or we are dealing with a camera artifact. If you disagree with my opinion, and you know the "facts" then please provide a counterargument.

Jeff.

Jeff, based on video I've seen, including the one I posted for you, I really don't believe that this photo is an accurate representation of the shaft's position during this interval, but rather is a "camera artifact". I have a really hard time believing that he could make any kind of consistent contact with a shaft that deflects that much, when he's swinging at 145 to 150 mph. His shaft likely looks more like Tiger's.

Bigwill

I am very sympathetic to your opinion that it is a camera artifact. The degree of shaft deflection appears "too large" to be mechanically possible. The only other explanation that makes sense to me is that he is deliberately choosing a very flexible shaft in order to get additional "kick". I will remain open-minded about this possibility, although I increasingly suspect that your "camera artifact" opinion may be correct.

Jeff.

Quote:

Originally Posted by Jeff (Post 59234)

I have to admit, I was a little disappointed in the camera that they used for that sequence when I picked up that issue. It looks like he's swinging a water hose :)

According to Golf digest, he's hitting a double-x flex that's tipped more than an inch, so it isn't too flexible. Plus you have to remember that at the speeds these guys generate, spin and control are huge issues, and my guess is that a shaft that's flexible enough to look like that would be more harmful than helpful in regards to those.

Bigwill

I wonder if he used a flexible shaft just for the GD camera shoot, in order to accentuate that "visual effect". I don't know - I am just guessing!

Jeff.

Quote:

Originally Posted by Jeff (Post 59237)

Bigwill

I wonder if he used a flexible shaft just for the GD camera shoot, in order to accentuate that "visual effect". I don't know - I am just guessing!

Jeff.

With an extra 250 large in his pocket, and club sponsorship deals, I'm sure he can afford to replace it after it snapped :)

Yodas Luke

You wrote-: "Might I suggest another golf website where pontificating and verbal defecation are the modi operandi?"

Yoda has kindly provided me with this forum where I can freely express my opinions (even if they represent in your mind "verbal defecation"). You are not obliged to visit this forum. Yoda has already stated that he has posted a "caveat emptor" sign in front of this forum. What excuse do you have for entering this forum and then complaining about the "quality" of my posts.

By the way, why do you have to have the psychological need to pontificate about an obvious typo error?

Jeff.

"kindly provided"

Quote:

Originally Posted by Jeff (Post 59239)

A. Your quote: "Yoda-I have been deciding whether to respond to your last post. Your tone is demeaning and ill-conducive to an ongoing debate. Why can't you simply state your disagreements without pontificatiing, and implying that you are the final arbiter of the "truth"?"

Although I enjoy the depth and nature of many of your posts, I find the above quote offensive. That is, if you are suggesting that Yoda is trying to be pompous or supercilious. In this forum, he is the judge and the jury. Until you start your own website, that’s the law. Enjoy the scenery or find your own pasture.

B. Your quote: “What excuse do you have for entering this forum and then complaining about the "quality" of my posts?”

I have been with Yoda from the beginning. I am a Senior Instructor with this website and I am responsible for some of the content. I need no other excuse.

I’m invoking my right as the “anybody else” in the following quote:
“That doesn't bother me. You, or anybody else, is free to criticise me as much as they want.”

C. Your quote: ”By the way, why do you have to have the psychological need to pontificate about an obvious typo error?”

I have an unfair pet peeve about people using big words and not spelling them correctly. I never “criticise” anyone, but I often criticize. At least I haven’t caught you using “your” as a contraction.

D. I would like to sincerely apologize to you if you assumed that the part of my quote, “verbal defecation”, was directed at your posts. When I thought of a place where the true Pontiff of the Universe reigned supreme, the “verbal defecation” also came to mind. In no way did I mean for that to be a reference to you or your posts. That part was solely directed at the other website. I hope you’ll trust in my stated intent.

Unfinished Business

Quote:

Originally Posted by Jeff (Post 59229)

Yoda - you stated-: "Then again, that's why I've created this Golf By Jeff Forum and given you domain. Here you can pick things apart to your heart's content and enjoy relative freedom from my comment . . ."

However, I resent the following series of statements-: "Yet, you then totally deep-end and restate to your own end basic laws of physics that have been accepted since the time Isaac Newton wrote his Philosophiæ Naturalis Principia Mathematica (1687). You put up a lot of good stuff, Jeff, but man, you make it difficult to sit idly by as you reinvent concepts that have served mankind well for centuries. --- To me, that's arrogance."

I am obviously not attempting to reinvent Newtonian laws. I may be misunderstanding them, or misrepresenting them - but I am not arrogantly reinventing them. You know that! Also, if I am so obviously wrong, why didn't you bother to show me my errors by means of an explanatory logical argument?
[Bold emphasis by Yoda.]

Jeff,

The facts in my posts #154 and #157 presented my argument (without, BTW, wearing out my readers). I'm done on this one. Per my advance notice above, I have entered the "enjoy relative freedom from my comment" phase. Enjoy!

:happy3:

Meanwhile, for old times sake, there are at least two pieces of unfinished business on the table that I would appreciate your cleaning up:

From my post #129:

Quote:

Originally Posted by Yoda (Post 59127)

Jeff,

BTW, you state that you see in my photos a "phenomenon that [you] have seen many times previously. Before release, the clubshaft is bent backwards and after release the clubshaft is bent forward." Question: How do you explain "The Snake" (Photo #4 in my post #127 above), where "after release", the Shaft simultaneously is bent both backwards and forwards?

:scratch:

Please include the photo in your reply, and for the visually-challenged among us, please trace the Shaft with a yellow line. Thanks!

And from my post #150:

Quote:

Originally Posted by Yoda (Post 59174)

Jeff,

Assume a tethered ball in orbit around an axis. Does the tether (and its tension) serve as the centripetal force of that action? If not, what does? If so, how does that differ from the concept of the clubhead tethered to its center (left shoulder) by the left arm and clubshaft?

:)

Thank you for your attention.

:salut:

Yodas Luke

You wrote with respect to Yoda-: "he is the judge and the jury."

That is correct. However, my affection for Yoda, and my presence on this website, is predicated on the belief that Yoda will be a wise and fair judge and that he will not be prejudiced to such a degree that he would censor a forum member's sincere opinions. As long as Yoda adheres to that high standard, I have no reason to seek another golf website, like the one run by the "Italian Stallion" who will not tolerate anyone questioning his "high priest" wisdom.

You also stated that as a Senior Instructor, you have the responsibility for this site's contents and that you also have the right to criticise my posts. That is correct. I have forthrightly stated that I eagerly seek insightful criticism that will strenuously test the legitimacy of my opinions regarding the golf swing. The only way that I can know whether my ideas are solid is to test them for their falsifiability factor in an open forum. If my ideas can be easily falsified, then I obviously need to modify them to make them more "true".

My only objection to criticism is when it is targeted at me in an ad hominem way, and where the tone of the posts is very demeaning/belittling. I may be stupid and often wrong, but I am sincerely trying to seek the "truth". I may appear arrogant and bombastic when I argue passionately for the "truth" of my personal opinions, but I do not indulge in ad hominem attacks. If you look at the contents of my posts, they are very targeted at arguing about the issues - even if you think that my arguments are wrong-headed. If forum members thinks that my arguments are illogical, they simply have to provide a counterargument that demonstrates my lack of insight. They don't have to add supplementary belittling remarks.

I did presume that you regarded my posts as verbal defecation, which is the chief reason why I became sufficiently invoked to respond to your posts. I accept your "corrective" explanation, and I am willing to move on without harboring any grudges. I don't know you personally, and I have every reason to believe that you are a very nice person, who I would very much like to meet someday.

Jeff.

Yoda - I cannot address your first question re: post #123 because I cannot locate that post. Post #123 was not your post.

I will offer my opinion regarding your second question.

You asked-: "Assume a tethered ball in orbit around an axis. Does the tether (and its tension) serve as the centripetal force of that action? If not, what does? If so, how does that differ from the concept of the clubhead tethered to its center (left shoulder) by the left arm and clubshaft?"

I do not think that the tether (and its tension) of the tethered ball in orbit represents as the centripetal force. I think the centripetal force is derived from the movement of the hand in a circular manner (when the hand moves from position A to position B in the following diagram), and the taut string only transmits the centripetal force to the orbiting ball. The string is continuously taut with no variation in its degree of tension - and therefore it is not a source of the centripetal force. It is only the conduit whereby the centripetal force (the force that keeps the orbiting ball traveling in a circle) is transmitted from the hand to the ball.

By analogy, the left arm/clubshaft combo does not create any centripetal force. It only serves as conduit whereby a centripetal force is transmitted to the clubhead. The source of the centripetal force is the movement of the left hand in a circular arc. The left hand moves in a circular arc secondary to a combination of two motions - the arc-like movement of the left shoulder socket in space, and the arc-like movement of the left arm which is suspended from the left shoulder socket, which acts as its fulcrum point.

Jeff.