The words centripetal and centrifugal in physics have their dictionary meanings. centripetal=toward the centre, centrifugal=away from the centre. They are equal and opposite, action and reaction.
Most people get it wrong because they do not understand that the centripetal force acts on the stone, and the centrifugal force acts on the string (or the boy). We then get incorrect statements about the centrifugal force throwing the rock out and keeping the string taut and that sort of thing.
What keeps the string taut? The boy pulling on it.
What balances the centripetal force on the stone? Nothing, that's why it moves in a circle.
As a general rule, the more words used to describe the phenomenon,
the more errors will be introduced.
Last edited by golf_sceptic : 06-26-2006 at 09:33 PM.
The words centripetal and centrifugal in physics have their dictionary meanings. centripetal=toward the centre, centrifugal=away from the centre. They are equal and opposite, action and reaction.
Most people get it wrong because they do not understand that the centripetal force acts on the stone, and the centrifugal force acts on the string (or the boy). We then get incorrect statements about the centrifugal force throwing the rock out and keeping the string taut and that sort of thing.
What keeps the string taut? The boy pulling on it.
What balances the centripetal force on the stone? Nothing, that's why it moves in a circle.
As a general rule, the more words used to describe the phenomenon,
the more errors will be introduced.
Regardless of terminology, I have seen Golfers swing a clubhead attached to a 48" rope. They swing this rope club and hit the ball. The ball goes far. Longer than I am with a graphite shaft. Whatever name you use to identify the forces involved, we know that very great forces were involved, more than muscle power can generate. And it makes your list of power sources look a little inapplicable.
Originally Posted by golf_sceptic
Sources of power in the golf swing (focussed on the club)
1. early in the downswing -- leverage through "locked" wrists
2. mid-downswing to impact -- the slingshot (or flail) effect
together with leverage applied through the hands.
Regardless of terminology, I have seen Golfers swing a clubhead attached to a 48" rope. They swing this rope club and hit the ball. The ball goes far. Longer than I am with a graphite shaft. Whatever name you use to identify the forces involved, we know that very great forces were involved, more than muscle power can generate.
Yes. I remember Wedgy Winchester (US pro who toured Australia in the 70s
and gave trick shot demos) and his rubber hose shafted club well. There
was centrifugal force at work there as well, but not on the clubhead!
Quote:
And it makes your list of power sources look a little inapplicable.
Nope. The power comes from the second of the sources -- the flail or slingshot effect. This is what Homer incorrectly labelled as centrifugal.
Let's not get distracted though. It's not my theories that are under the spotlight. It's simply the misunderstanding of centrifugal force in Homer's writings (and most explanations) that is at stake. That's all. No more. No less. I'm more than happy to explain the physics correctly and let others ponder on the implications for TGM. In my book it doesn't change the teaching principles one little bit.
Last edited by golf_sceptic : 06-27-2006 at 12:43 AM.
The words centripetal and centrifugal in physics have their dictionary meanings. centripetal=toward the centre, centrifugal=away from the centre. They are equal and opposite, action and reaction.
Most people get it wrong because they do not understand that the centripetal force acts on the stone, and the centrifugal force acts on the string (or the boy). We then get incorrect statements about the centrifugal force throwing the rock out and keeping the string taut and that sort of thing.
What keeps the string taut? The boy pulling on it.
What balances the centripetal force on the stone? Nothing, that's why it moves in a circle.
As a general rule, the more words used to describe the phenomenon,
the more errors will be introduced.
Centrifugal force is a convenient term describing an effective force present on objects in a rotating reference frame (an object undergoing centripetal acceleration). It is what our bodies, arms, and hands "feel" as the pulling away from the center of rotation during a swing. This concept and feel can be used as an aid to creating angular velocity. That is all that is claimed within TGM to my knowledge. Angular velocity and acceleration is what ultimately matters.
__________________ _________________________________
Steph
Distance is Magic; Precision is Practice.
Centrifugal force is a convenient term describing an effective force present on objects in a rotating reference frame (an object undergoing centripetal acceleration).
Yes, but everything gets a whole lot harder once you start using non-inertial frames of reference. Bear in mind also that in a non-inertial frame of reference such as that viewed using a camera attached to the clubhead, the centrifugal force neatly balances the centripetal force and the clubhead remains still in the camera's eye as does the centre of the motion. Only the objects not attached to the clubhead appear to be flung outward. Again, the clubhead is not accelerated outward by centrifugal force in that or any other useful frame of reference because centrifugal force does not act on the clubhead.
The "throw out" effect is real. It is not, however, created by centrifugal force.
Quote:
It is what our bodies, arms, and hands "feel" as the pulling away from the center of rotation during a swing.
Yes. 100% correct. The reaction to our pulling inward (centripetal force) is the outward (or centrifugal) force that we feel and it acts on our bodies (not on the clubhead).
Quote:
This concept and feel can be used as an aid to creating angular velocity.
Nope. As you so clearly pointed out, the centrifugal force acts on us not the clubhead.
Quote:
That is all that is claimed within TGM to my knowledge. Angular velocity and acceleration is what ultimately matters.
Correct. The TGM concept of centrifugal force is wrong. Angular velocity and acceleration are paramount, but that is a topic for another day!
Last edited by golf_sceptic : 06-27-2006 at 01:12 AM.
Don't know why but this extract keeps springing to mind.
`And only one for birthday presents, you know. There's glory for you!'
`I don't know what you mean by "glory",' Alice said.
Humpty Dumpty smiled contemptuously. `Of course you don't -- till I tell you. I meant "there's a nice knock-down argument for you!"'
`But "glory" doesn't mean "a nice knock-down argument",' Alice objected. `When I use a word,' Humpty Dumpty said, in rather a scornful tone, `it means just what I choose it to mean -- neither more nor less.' `The question is,' said Alice, `whether you can make words mean so many different things.'
`The question is,' said Humpty Dumpty, `which is to be master -- that's all.'
Alice was too much puzzled to say anything.
Would it be cool if Homer was 100% right on everything? Hell yes.
What if he isn't? TGM gonna go down in flames? Hell no.
We're talking about small things here.
It's most important to get this right....
We have to remember.....when Homer died he had not hung up his "golf researchin pants"....so let's not....
Hi Birdie_Man. As you started this thread and welcomed the debate, you may be one of the last objective participants. If so, for your information, here is "Centrifugal force" from a neutral, namely Encyclopedia Britannica.
"Centrifugal Force, quantity, peculiar to a particle moving on a circular path, that has the same magnitude and dimensions as the force that keeps the particle on its circular path (the centripetal force) but points in the opposite direction. A stone whirling in a horizontal plane on the end of a string tied to a post on the ground is continuously changing the direction of its velocity and, therefore, has acceleration toward the post. This force is equal to the square of its velocity divided by the length of the string According to Newton’s second law; acceleration is caused by a force, which in this case is the tension in the string. If the stone is moving at a constant speed and gravity is neglected, the inward-pointing string tension is the only force acting on the stone. If the string breaks, the stone, because of inertia, will keep on going in a straight line tangent to its previous circular path; it is not the influence of a centrifugal “force” that will make the stone fly off in a radially outward direction.
Although it is not a real force according to Newton’s laws, the centrifugal-force concept is a useful one. For example, when analyzing the behaviour of the fluid in a cream separator or a centrifuge, it is convenient to study the fluid’s behaviour relative to the rotating container rather than, relative to the Earth; and, in order that Newton’s laws be applicable in such a rotating frame of reference, an inertial force, or a fictitious force (the centrifugal force), equal and opposite to the centripetal force, must be included in the equations of motion. In a frame of reference attached to the whirling stone, the stone is at rest; to obtain a balanced force system, the outward-acting centrifugal force must be included.
Centrifugal force can be increased by increasing either (1) the speed of rotation, (2) the mass of the body, or (3) the radius, the distance of the body from the centre of the curve. Increasing either the mass or the radius increases the centrifugal force proportionally, but increasing the speed of rotation increases it in proportion to the square of the speed; that is, an increase in speed of 10 times, say from 10 to 100 revolutions per minute, increases the centrifugal force by a factor of 100. Centrifugal force is expressed as a multiple of g, the symbol for normal gravitational force (strictly speaking, the acceleration due to gravity). Centrifugal fields of more than 1,000,000,000 g have been produced in the laboratory. "
Hi Birdie_Man. As you started this thread and welcomed the debate, you may be one of the last objective participants. If so, for your information, here is "Centrifugal force" from a neutral, namely Encyclopedia Britannica.
"Centrifugal Force, quantity, peculiar to a particle moving on a circular path, that has the same magnitude and dimensions as the force that keeps the particle on its circular path (the centripetal force) but points in the opposite direction. A stone whirling in a horizontal plane on the end of a string tied to a post on the ground is continuously changing the direction of its velocity and, therefore, has acceleration toward the post. This force is equal to the square of its velocity divided by the length of the string According to Newton’s second law; acceleration is caused by a force, which in this case is the tension in the string. If the stone is moving at a constant speed and gravity is neglected, the inward-pointing string tension is the only force acting on the stone. If the string breaks, the stone, because of inertia, will keep on going in a straight line tangent to its previous circular path; it is not the influence of a centrifugal “force” that will make the stone fly off in a radially outward direction.
Although it is not a real force according to Newton’s laws, the centrifugal-force concept is a useful one. For example, when analyzing the behaviour of the fluid in a cream separator or a centrifuge, it is convenient to study the fluid’s behaviour relative to the rotating container rather than, relative to the Earth; and, in order that Newton’s laws be applicable in such a rotating frame of reference, an inertial force, or a fictitious force (the centrifugal force), equal and opposite to the centripetal force, must be included in the equations of motion. In a frame of reference attached to the whirling stone, the stone is at rest; to obtain a balanced force system, the outward-acting centrifugal force must be included.
Centrifugal force can be increased by increasing either (1) the speed of rotation, (2) the mass of the body, or (3) the radius, the distance of the body from the centre of the curve. Increasing either the mass or the radius increases the centrifugal force proportionally, but increasing the speed of rotation increases it in proportion to the square of the speed; that is, an increase in speed of 10 times, say from 10 to 100 revolutions per minute, increases the centrifugal force by a factor of 100. Centrifugal force is expressed as a multiple of g, the symbol for normal gravitational force (strictly speaking, the acceleration due to gravity). Centrifugal fields of more than 1,000,000,000 g have been produced in the laboratory. "
Aw man why me.....too early for this stuff (I know it's 11:46 but I just got up....hey- it's summer time )....
KK I'll try....
...
I realize that CF isn't (by definition) a "FORCE"....
Reactive force would u call it? I dunno.
Whatever you want to call it....I don't think you can deny that the effect is there.
Anyway.....but what does it DO in the golf swing? And what does Homer SAY it does? And.........what CAUSES the Release....what does Homer say causes it? (anything else? That's all I can think of...)
I guess those are the issues.
It's obviously there at some point (I'm thinkin only beyond the Release...but I'm not sure).....so does it do anything really?
Dunno that I can answer that.
....
I haven't been following this thread too much....haven't been reading the massive posts BTW.
....
Part of me says that Homer must've known some of this stuff.....Centripetal, etc.....I think I remember reading something about "him just sticking with calling it CF because....." (something about it being a well-known term or something).....
....but that still doesn't make it make much sense to me.....you'd think Homer woulda said "Screw what everyone wants to call it....I'm gonna write my own book..."
...
Ya that's all I can give you right now I think....brain says nuh-uh.
...
BTW I dunno if I'm the only one who wants to see a summary of positions (i.e. your stance on the issues.....your beefs, etc.....don't have to summarize this whole thread or anything)....for both "sides" I guess. Catch everyone up and get everyone's heads on straight again.
Last edited by birdie_man : 06-30-2006 at 12:08 PM.
)....
Hybrid Mode
