playful exercise
- Thread starter mandrin
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mandrin
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JonWil, the details for the solution are to be found here. Not being related to a golf swing it still might give some intuitive insight into velocity multiplication when reducing swing radius........ small mass at the distal end and fairly large proximal mass rather close, but not too close, to the center.
JonWil, the details for the solution are to be found here. Not being related to a golf swing it still might give some intuitive insight into velocity multiplication when reducing swing radius........ small mass at the distal end and fairly large proximal mass rather close, but not too close, to the center.
Good stuff. I must admit I didn't see the problem with energy conservation for C as I cheated a little. As you only asked for relative speeds I neglected the first phase as they're all the same. So I took time zero as when the pin engaged and didn't worry about the collision. Us engineers are lazy like that (I like to think I'm efficient and practical).
Out of interest, is that where you were going with the figure right at the bottom of the page. Couldn't make it out on my phone but it looks like an energy balance.
My premise was somewhat off the mark
Interesting stuff mandrin, thanks.
It would appear that fat boys with long light-headed drivers have an advantage. Just kidding...
no worries. I bet your physics is better than my golf, although I am a scratch engineer
mandrin
New
Oliver1,
I like the part just playing around. Generating a final reasonable product takes time, such as making up figures and making sure all the nitty-gritty details are been taking care of. Short answer, it takes more time than I like to admit.
Thanks for that Mandrin.Oliver1,
I like the part just playing around. Generating a final reasonable product takes time, such as making up figures and making sure all the nitty-gritty details are been taking care of. Short answer, it takes more time than I like to admit.
On a related note, Would it be viable to come up with mathematical proofs for some complete arbitrary "perfect golf swing?" I appreciate that not only would you have proofs for isolated areas of the movement, as in your original puzzle, but also to prove the interrelatedness of it all. How long, if ever, would it take before you hit a point of diminishing returns?
Thanks once again for your response, Mandrin. A layman like me is fascinated with this little medley...
mandrin
New
leon,
The figure at the bottom ties everything together. Hence for the particular values chosen it shows the speed of the mass m1 at the bottom for A,B, C and D.
ok thanks. I'll look at it on my laptop, I might be able to read it then!
mandrin
New
Oliver1,
How long, if ever, would it take before you hit a point of diminishing returns?
Interesting question. I feel that a point of diminishing return is reached perhaps rather quickly. There is a consensus that a pure mathematical model of a golfer already quickly looses its value beyond a double or triple pendulum model. Too many assumptions have to be made quickly stripping it from being able representing a typical golfer's swing.
As soon as you start using more complex 3D models of a golfer you are forced to go towards an intricate mixture of forward and inverse dynamics. Hence using both math models to derive motion from known imposed forces/torques but also using kinematic measurements using real golfers to find out about real forces/torques.
It is all quite sophisticated with complicated data acquisition systems and associated data processing and filtering in addition to the complex 3D mathematical model. However as usually with research it produces not readily simple results. Golfers are very different in the way they use their body to execute a golf swing.
So don't expect in the near future a simple how to do book based on golf research. It will more likely be slowly converging towards a set of basic concepts on which to build a sound teaching method. Such I think is Brian's goal. Golf instruction based on a set of basic ideas/concepts conformed by and continuously updated by scientific research.
I do think that those who like to think of golf primarily as an art and do not like the intrusion of science in golf can still hope that this will not change overnight.
Would there eventually be one ideal golf swing? I hope not, what a misery looking at pros appearing to be coming from the same assembly line.
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Jim Kobylinski
Super Moderator
Oliver1,
How long, if ever, would it take before you hit a point of diminishing returns?
Interesting question. I feel that a point of diminishing return is reached perhaps rather quickly. There is a consensus that a pure mathematical model of a golfer already quickly looses its value beyond a double or triple pendulum model. Too many assumptions have to be made quickly stripping it from being able representing a typical golfer's swing.
As soon as you start using more complex 3D models of a golfer you are forced to go towards an intricate mixture of forward and inverse dynamics. Hence using both math models to derive motion from known imposed forces/torques but also using kinematic measurements using real golfers to find out about real forces/torques.
It is all quite sophisticated with complicated data acquisition systems and associated data processing and filtering in addition to the complex 3D mathematical model. However as usually with research it produces not readily simple results. Golfers are very different in the way they use their body to execute a golf swing.
So don't expect in the near future a simple how to do book based on golf research. It will more likely be slowly converging towards a set of basic concepts on which to build a sound teaching method. Such I think is Brian's goal. Golf instruction based on a set of basic ideas/concepts conformed by and continuously updated by scientific research.
I do think that those who like to think of golf primarily as an art and do not like the intrusion of science in golf can still hope that this will not change overnight.
So in translation, there will be no book on how to perfectly skin a cat?
Good, because most people love their method.
--------
Thanks Mandarin, really good stuff.
Mandrin,
You, Sir, are a delight. Thanks for taking the time to answer. Unfortunately Mother Nature bestowed upon me a rather spiteful combo: Enough tenacity to keep trying to figure stuff out, but a dearth of intellectual wherewithal with which to do so. Makes for exhausting days, for sure!
Thanks once again...
Olly
You, Sir, are a delight. Thanks for taking the time to answer. Unfortunately Mother Nature bestowed upon me a rather spiteful combo: Enough tenacity to keep trying to figure stuff out, but a dearth of intellectual wherewithal with which to do so
. Makes for exhausting days, for sure!Thanks once again...
Olly
mandrin
New
This is getting pathetic.....
This is getting really pathetic. This is kindergarten stuff. Are these really adults I am dealing with? It almost starts getting funny. Since being banned from this forum poor nmgolfer has really started to show why he has never been able to stay on any forum for any extended period of time.
Now being relegated to a tiny satellite forum where basically there are only two posters, nmgolfer and jeffmann, they both are scrutinizing BM's forum for any small crumb falling from the table to have at least something to debate. Poor fellows.
The newest contribution from nmgolfer is meant to yet another time discredit mandrin, any way possible. Let's look what it is all about. I really wonder why I should waste my time with these neanderthalers.
Nmgolfer employs his usual approach. Quickly sneaking in, planting his knife and rushing away pretending that it would really take too much of his time to really explain what it is all about. He relies on the fact that most either are not interested or understand his nonsense, but hoping that something will stick.
He again really tries to make a big fuss about a small detail and doing so showing the fool he really is, making actually a stupid mistake himself.
“Consider case C.
Motion of a double pendulum is far more complex that what Mandarin naively assumes. And he makes an egregious error when he assumes:
V2 = V1(x2/x1) ....
Uh... no.... that would be true only if a rigid rod connected the mass' to the pivot. But he explicitly states that is not the case, that a flexible massless steel cable connects them. “
Poor little fellow, so darned anxious to find something to discredit mandrin he completely forgets to read what is actually written in my post.
“A thin rigid massless rod has mass and *hook attached as shown in the Figs 1 to 4.
The whole manoeuvre is not really about any scientific point but simply yet another pretext for slandering and mud slinging.
It surprises me that this Richie3Jack, to be so extremely naïve, whilst admitting that science is way above his head, so quickly falling in love with this bully. He is definitely loosing his face here. One normally expects a moderator/administrator to show a bit more discernment.
A useful quote for Richie3Jack:
People are very inclined to set moral standards for others.* ~Elizabeth Drew,*The New Yorker, 16 February 1987
This is getting really pathetic. This is kindergarten stuff. Are these really adults I am dealing with? It almost starts getting funny. Since being banned from this forum poor nmgolfer has really started to show why he has never been able to stay on any forum for any extended period of time.
Now being relegated to a tiny satellite forum where basically there are only two posters, nmgolfer and jeffmann, they both are scrutinizing BM's forum for any small crumb falling from the table to have at least something to debate. Poor fellows.
The newest contribution from nmgolfer is meant to yet another time discredit mandrin, any way possible. Let's look what it is all about. I really wonder why I should waste my time with these neanderthalers.
Nmgolfer employs his usual approach. Quickly sneaking in, planting his knife and rushing away pretending that it would really take too much of his time to really explain what it is all about. He relies on the fact that most either are not interested or understand his nonsense, but hoping that something will stick.
He again really tries to make a big fuss about a small detail and doing so showing the fool he really is, making actually a stupid mistake himself.
“Consider case C.
Motion of a double pendulum is far more complex that what Mandarin naively assumes. And he makes an egregious error when he assumes:
V2 = V1(x2/x1) ....
Uh... no.... that would be true only if a rigid rod connected the mass' to the pivot. But he explicitly states that is not the case, that a flexible massless steel cable connects them. “
Poor little fellow, so darned anxious to find something to discredit mandrin he completely forgets to read what is actually written in my post.
“A thin rigid massless rod has mass and *hook attached as shown in the Figs 1 to 4.
The whole manoeuvre is not really about any scientific point but simply yet another pretext for slandering and mud slinging.
It surprises me that this Richie3Jack, to be so extremely naïve, whilst admitting that science is way above his head, so quickly falling in love with this bully. He is definitely loosing his face here. One normally expects a moderator/administrator to show a bit more discernment.
A useful quote for Richie3Jack:
People are very inclined to set moral standards for others.* ~Elizabeth Drew,*The New Yorker, 16 February 1987
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Brian Manzella
Administrator
Oooh, we're playing quotes!!!
Goody, goody!!
Here's a shoe that should fit:
Goody, goody!!
Here's a shoe that should fit:
Anyone who has declared someone else to be an idiot, a bad apple, is annoyed when it turns out in the end that he isn't. —Nietzsche
mandrin
New
I am afraid that nmgolfer might feel left out without being honored with a proverb being dedicated to him. I looked for one and selected a Mexican proverb.
"Stupidity closes the door of kindness"
I noticed that his forum has been taken offline. That should not be a problem as Richie3Jack will provide him a place in his free-for-all forum..."like attracts like".
"Stupidity closes the door of kindness"
I noticed that his forum has been taken offline. That should not be a problem as Richie3Jack will provide him a place in his free-for-all forum..."like attracts like".
Mandrin-
A question for you. I looked at your puzzle and reached an intuitive conclusion D, then A and B the same, and no idea about C whatsoever. I perused your explanation but it would take my math-challenged brain about two days to work through the analysis to actually understand it -- so I took a pass.
But intuitively I was imagining that since I would have to pull on the thin rod much harder to create the D path (going normal is real work if you want faster clubhead speed) than the A and B path that that "work" would have to be converted into a faster moving object on the end of the rod. Is there anything to this intuitive idea in the context of your puzzle?
A question for you. I looked at your puzzle and reached an intuitive conclusion D, then A and B the same, and no idea about C whatsoever. I perused your explanation but it would take my math-challenged brain about two days to work through the analysis to actually understand it -- so I took a pass.
But intuitively I was imagining that since I would have to pull on the thin rod much harder to create the D path (going normal is real work if you want faster clubhead speed) than the A and B path that that "work" would have to be converted into a faster moving object on the end of the rod. Is there anything to this intuitive idea in the context of your puzzle?
mandrin
New
niblick1,
Your post is very interesting since it shows that the suggestion of shortening the swing radius I had planted did operate. The case D shows indeed a shortening of swing radius but importantly there is no work done on the mass m1. If the same shortening of swing radius had been accomplished in D by pulling on a cord through the center, yes indeed than it would confirm to your intuitive approach.
It is kind of tricky business. I explained it in Miura - parametric acceleration. The mass moves inwards due a centripetal force acting on it and hence positive work is being done and subsequently kinetic energy being generated. But that does not really make it clear why the mass gets a greater tangential speed.
It can be understood considering that the inward motion of the mass due to a centripetal force creates a slight deviation from 90 degrees between direction of motion and centripetal force, resulting in a tangential force component, leading to increased tangential speed.
Your intuition is working on the right track. Perhaps a pity but in golf, as everything else in life, you don't get get much for free. It usually takes an effort.
niblick1,
Your intuition is working on the right track. Perhaps a pity but in golf, as everything else in life, you don't get get much for free. It usually takes an effort.
Ouch! Fair answer, though. Thanks.
mandrin
New
niblick1,
I wonder if their is perhaps some ambiguity in my post. To make sure I am referring solely to the fact that there is no free perpetual motion effect and that always work has to be done when looking for more speed.
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