Thank you for your explanation of the effect of water drag load on the limits of a waterskier's physical ability to maintain a curved path. That makes the waterskier analogy less useful. Hopefully, other forum members will imagine the waterskier situation as an "imaginary situation" that exists in the absence of any water drag load, so that they can basically try to get a visual picture of nm golfer's mathematical explanation. I wonder if there is a better visual analogy that can better convey the "essential idea" behind his mathematical explanation, which seems to be very sound.
Jeff.
I would have said Thank You to Baggerfor taking the time to explain instead pissing on him. Maybe on your other forum this is protocol.
You wrote-: "would have said Thank You to Baggerfor taking the time to explain instead pissing on him."
Wow! I am flabbergasted at this comment. I did thank Bagger. I wasn't insulting him. I acknowledged his greater knowledge re: the effect of water drag load on a waterskier's skis, and I therefore concluded that I would need to find another visual analogy to better illuminate nmgolfer's mathematical explanation.
You wrote-: "would have said Thank You to Baggerfor taking the time to explain instead pissing on him."
Wow! I am flabbergasted at this comment. I did thank Bagger. I wasn't insulting him. I acknowledged his greater knowledge re: the effect of water drag load on a waterskier's skis, and I therefore concluded that I would need to find another visual analogy to better illuminate nmgolfer's mathematical explanation.
Jeff.
I find you being flabbergasted hold to imagine. But nothing personal ol chap. It's just you seem less than affable in many replies. Not many rocket scientists on this site but a whole lot of good golfers that know how the sweet spots moves on plane to achieve impact.
First of all, Thank you Jeff for asking some very interesting questions regarding TGM - in this thread as well as in others.
And even though the endless belt analogy has some merits, I certainly agree that concepts that are close to the real thing are better than those who are farther away.
But angular acceleration isn't what this is about. Angular acceleration is often regarded as one of the most differentiating factors between swinging and hitting, and is possible one of the most misunderstood concepts in golf.
Angular acceleration does not increase the speed of whatever is being rotated. Angular acceleration doesn't do anything but change the direction while conserving energy. It is only longitudinal force that can increase the club spead. Or shoud I say: "Geometrically Orienteted Linear Force" - G.O.L.F
In a pure swing, the swing center is shifting. It is always moving a little ahead of the rotation center. Rotation of left shoulder joint is key here. I personally believe that the role, position and movement of the left shoulder joint is underestimated in TGM as far as swinginging is conserned.
This shifting of center is creating a longitudinal force component in addition to the centripetal force component of the "pulling string". The pulling string is used to pull & rotate at the same time. The longitudinal force component is what increases speed. The centripetal force component only takes care of the circular part and doesn't produce speed.
Think of David Leadbetters illustration when he spins a little something attached to a tiny rope. He has to move his hand in a circle to pick up speed.
Only longitudinal force produces work. And work is required to increase the speed. It is the longitudinal force of the swing that increases the clubhead speed. Or should I say: Geometrically Oriented Linear Force: G.O.L.F.
And Newton has explained why there is no other way.
It is possible to do a pure swing and a pure hit from the same top position, and have the same club alignment at impact and basically the same speed too. These facts are strong indications that the two stroking methods basically containes the same amounts of angular acceleration (the part that caused the rotation) and longitudinal acceleration (the part that increases the speed). One of them would miss the ball othervise.
I don't think the water skiing analogy works without water drag. It is the water drag that enables the skier to go in another direction than the boat, and this is a sort of overtaking action. As long as the skier is coming up from behind he will have larger speed than the boat - even relative to the course the boat is going. But the skier will have largest speed when he goes in the direction that is most different to the boat - when he comes back from a far left, is straight behind the boat and aiming far right. The true analogy to golf here is, I believe an overtaking action. A transfer of energy from boat to skier. A skilled and heavy skier will significantly slow down the boat. Some of the energy will be wasted to water shuffling, but some of it will accelerate him to the right.
If the boat went in circles, and managed to keep with up the skier, he could be straight behind the boat aiming far right and picking up speed all day long.
Looking at the Bobby Jones sequence, the swing seems to have a very steady linear force as the club is acellerating gradually.
Looking at Tiger's swing, something interesting seems to be happening around 9 o'clock in the downswing. Is the clubhead slowing down for a brief moment? Is he manipulating the geometry in order to increase the G.O.L.F from that point and through the ball?
Bernt - thanks for posting your opinion. I am always interested in reading other people's opinions, because I may learn something "new" that will change my mind about an "issue". Unfortunately, I first have to understand another person's opinion before I can change my mind, and I cannot understand many points that you seem to be expressing.
To start, you wrote-: "Angular acceleration does not increase the speed of whatever is being rotated. Angular acceleration doesn't do anything but change the direction while conserving energy. It is only longitudinal force that can increase the club spead. Or shoud I say: "Geometrically Orienteted Linear Force" - G.O.L.F."
I am not sure what you mean by longitudinal force. Consider nm golfer's mathematical explanation. He stated that the hands are always changing direction and speed at every moment of the downswing. Do you regard that as a longitudinal force, a G.O.L.F force? Secondly, he stated that if the hands are pulling the grip end of the club in the same direction that the hands are moving, and at the same speed as the hands are moving, that the clubhead end of the club would be angularly accelerated at every fractional time-point of the downswing, and that the cumulative effect of many thousands of time-points of angular acceleration inputs would cause the clubhead end of the club to progressively speed up. In other words, he is seemingly implying that angular acceleration doesn't only change the direction of the clubhead's movements, it also causes the clubhead end of the club to speed-up. Do you disagree? Secondly, nm golfer's mathematical explanation doesn't state anything about "conservation of energy" because there is not a "fixed" amount of energy in his hand/clubshaft system. The hands can constantly receive additional energy throughout the downswing from a variety of power sources (eg. release of power accumulator #4).
You also wrote-: "In a pure swing, the swing center is shifting. It is always moving a little ahead of the rotation center."
Could you please define "swing center" and "rotation center". I cannot develop a mental picture of your developing argument. You further wrote-: "This shifting of center is creating a longitudinal force component in addition to the centripetal force component of the "pulling string". The pulling string is used to pull & rotate at the same time. The longitudinal force component is what increases speed."
You seem to be implying that there is longitudinal force component that causes the increase in clubhead speed. What is this longitudinal force component and where is it operant in the PingMan machine's swing? If you are implying that the left shoulder socket is moving left-laterally in space, while the left arm rotates from the fulcrum point of the left shoulder socket point, and you are implying that the constant movement of the left shoulder socket in space represents the longitudinal force, how can the hands "know" what percentage of their force of forward movement comes from the movement of the left shoulder socket in space versus the rotational movement of the left arm?
Could you please explain what you see in Tiger's swing at 9 o'clock?
Bernt - thanks for posting your opinion. I am always
I am not sure what you mean by longitudinal force. Consider nm golfer's mathematical explanation. He stated that the hands are always changing direction and speed at every moment of the downswing. Do you regard that as a longitudinal force, a G.O.L.F force?
As a few other terms I used in the post, I could certainly have picked a better one. I should have used the term tangential force, ref my other post above.
I agree that the hands are always changing direction and speed. In addition, the hands transfer radial and tangential forces.
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Secondly, he stated that if the hands are pulling the grip end of the club in the same direction that the hands are moving, and at the same speed as the hands are moving, that the clubhead end of the club would be angularly accelerated at every fractional time-point of the downswing, and that the cumulative effect of many thousands of time-points of angular acceleration inputs would cause the clubhead end of the club to progressively speed up.
I was confucing "angular acceleration" with radial acceleration. Sorry about that.
I basically agree with the above, but I think it makes sense to decompose angular acceleration. Angular acceleration is created by radial acceleration and tangential acceleration. But it is only the tangential component that increases the swing speed.
There are basically two ways of generating tangential acceleration.
1) By applying torque (as in trying to bend the shaft)
2) By partly pulling the club in a direction that has a tangential component as well as the radial component.
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Secondly, nm golfer's mathematical explanation doesn't state anything about "conservation of energy" because there is not a "fixed" amount of energy in his hand/clubshaft system. The hands can constantly receive additional energy throughout the downswing from a variety of power sources (eg. release of power accumulator #4).
You also wrote-: "In a pure swing, the swing center is shifting. It is always moving a little ahead of the rotation center."
"Swing center" was another one of my ill-defined terms. Unfortunately, I don't have a good expression available at the moment. But what I mean is that the total force applied to the club (tangential and radial force) is not pointing at the rotation center. An offset is required to generate a portion of tangential force. This offset could be the location of left shoulder vs. head/neck which is likely to be the rotation center.
But may I restate that radial force only changes direction and conserves the velocity energy that has been transmitted to the clubhead so far in the swing.
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You seem to be implying that there is longitudinal force component that causes the increase in clubhead speed. What is this longitudinal force component and where is it operant in the PingMan machine's swing?
The pingman machine has its mechanical left arm attached to a mechanical shoulder. This shoulder is rotating arount the center of rotation, so that an offset is created.
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If you are implying that the left shoulder socket is moving left-laterally in space,
It is moving in an arch. How close this arch is to a circle probably varies from golfer to golfer. But the point is that the pulling must stay "ahead" of the swing center to increase speed. There i said it again. I meant center of rotation. "Swing center" is probably an equally correct phrase. But since I've already abused the term "swing center" i will try to let that rest at least in this thread.
But regardles of swing technique, somewhere in the body, torque must be applied. In a pure swing, torque is applied to rotate the left shoulder. And this torque enables the left shoulder to generate radial and tangential acceleration up on the club by simply pulling the arm.
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how can the hands "know" what percentage of their force of forward movement comes from the movement of the left shoulder socket in space versus the rotational movement of the left arm?
I don't understand this question.
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Could you please explain what you see in Tiger's swing at 9 o'clock?
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When the clubhead is around 10 o'clock, it is loosing speed beween two frames. If the illustration is correct. 10 o'clock as seen from our side, that is. I'm wondering whether there's some downstroke loading going on.
But it could as well be just an inaccuracy in the illustration.
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