Was Homer Wrong?

[golf_sceptic]

So I asked for a summary, probably won't get it but we will see.

Oh ye of little faith! Here it is...

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.

TGM
1. The most comprehensive theory on swinging a golf club
2. Contains some misconceptions which detract from
the frequent claims that it is based in physics but do not
detract from its usefulness as a teaching tool (eg centrifugal
force, endless belt effect, swinger v hitter dichotomy)
3. Suffers from non-standard use of terms which make for
confusing discussions (vertical is the worst in this regard)

Centrifugal force
1. One of the worst understood concepts in physics
2. Not a source of power in any context

For the record Martee's response to my summary
would enable me to write something much better
in the "sources of power" section if asked for
a summary now.

Just told them off...

Oh, so that's what your uninformative rant was.
I hope you felt better afterwords and earned
a few brownie points here following your boast.

I'll consider myself told, but you do realise you
were told off by one of the moderators at ISG
for your post don't you? You were well out of order.

Your rant won't stop me from explaining why centrifugal
force does not cause the "throw out effect", or
why the endless belt model is bogus, or explaining
why one or two of the definitions in the little
yellow book are complete gobbledegook, or continuing
to explore the hitter/swinger issue (ok red herring
is a bit strong).

As I say on ISG, let's suppose that there are a few
problems with the words of Mr Kelley. Will knowledge
of those flaws put TGM on firmer or shakier ground?

I'm happy with the path that I've chosen and
my knowledge of the Golf swing that I've acquired
from HK and this forum and its members and other TGM people.

...as you should be. Don't mistake my blasphemy as an
attempt to discredit TGM. I just think it would be
better if the high priests of TGM didn't have to paper over
the theoretical cracks quite as much. Surely anybody who knows
both physics and wants a bright future for TGM is
embarassed by the centrifugal force thing.

There's no need to feel threatened. We come in peace!

[Yoda]

Don't mistake my blasphemy as an attempt to discredit TGM. I just think it would be better if the high priests of TGM didn't have to paper over the theoretical cracks quite as much. Surely anybody who knows both physics and wants a bright future for TGM is embarassed by the centrifugal force thing.

Homer Kelley was well aware of the academic notion that Centrifugal Force is "artificial."

In fact, in our 1982 GSEM Class, he mocked his accusers in a purposely-pained voice: "There is no centrifugal force, son!"

Nevertheless, the concept as he defined it in the Glossary -- "The effort of the Swinging Clubhead to pull the Primary Lever Assembly (Left Arm and Club) into a straight line" -- is the essence of the Physics of Rotation. As any kid who has ever whirled a rock on a string could tell us.

And that is the important thing.

[annikan skywalker]

What would you call the equal and opposite force of Centrepetal Force...a "center fleeing" force of no known name?...I like the mystery of it..."The Unknown Force"..or better yet .... Let the "Unknown Force" be with you!!! Tee hee hee!!!

[golf_sceptic]

Homer Kelley was well aware of the academic notion that Centrifugal Force is "artificial."

That's a straw man argument. It works like this...
1. Say something your opponent didn't say
2. Tell everybody how wrong it is.
3. Draw the conclusion that your position must be correct.

For example
1. I heard <subject of ridicule> say that 2 + 2 = 7
2. We all know how silly that is.
3. Therefore 2 + 2 = 6

In the rock on the string example the rock is affected
by only one force. That is centripetal force and it is
what causes the rock to follow a circular path.

As a result of the string pulling on the rock, the rock
pulls on the string with an equal and opposite force.
That is the centrifugal force.

Going further, the boy pulls on the string (centripetal)
and the string pulls on the boy (centrifugal).

To balance the pull from the string, the boy leans back
ever so slightly and uses gravity to balance himself.

Too easy, but so many teachers, students, professors,
NASA educationalists and so on get it wrong.

There most certainly is a centrifugal force at work,
but it does not act on the stone.

Mock away, but Homer got it wrong. So did the flat earth theorists.

Before anybody asks, the "throw out effect" is real. It just has nothing
to do with centrifugal force. And that is the important thing!

Do you want to do the endless belt now, or chew on this one for a while?

[Daryl]

Golf Sceptic,

You've said what you wanted to say. This is not my website but by the amount of and tone of your posts, you may have come looking for disagreement and argument. This forum is friendly and accommodating. People are drawn to this forum who find the information insightful and useful. If you've read the book and have a question, then members will respond the best they can. If you have a problem with your golf swing then the members will also step-up-to-the-plate, and help you the best they can. This is all we can possibly do for each other.

If you want to debate physics and Centrifugal Force, then perhaps you would be better accommodated on a Physics Forum. There you may find people with your like interests and knowledge and share insight into that subject. You may be happier somewhere else, however with your knowledge of physics you could become a helpful member here. Just remember that we don't 'burn bridges' here, so you may have to 'bite your tongue' once-in-awhile.

Good luck Down Under.

[kmmcnabb]

This is not the place for heated arguments. There are many other forums to go to for that so be civil or be gone.

That being said......

While I don't agree with how things are put in TGM (really poorly written, even for an engineer) and some definitions have been shown not to be as good as they could have been...I am not an expert so I can't argue there. What I do know is that you can't argue with what works.

Get the book, get an AI and/or use this forum, and and see how your game improves. I do agree that TGM it is not the end all for learning GOLF but I have been trying to play (emphasize trying) for over 20 years. My single greatest gains have been in learning more using TGM. Learning correct alignments and how the FLW/BRW works is worth the time and energy involved. Everything else is gravy. Spend a month doing small chips, then pitches and see what happens.

By the way, went from weekend golfer, no real practice and average of 100 plus to shooting in the mid 80s with no AI (took about 7 months). I expect, when I get a chance to visit Lynn, it will get even better. My brother in law is a scratch golfer for 20 years using TGM (he learned from an AI in the 80s). He got me onto TGM (twice, first time didn't take).

By the way, I have played a fade (or slice) for over 20 years. As of today, I draw the ball or hit is dead straight and everyone that has asked my advice on reading the book have been both surprised and rewarded with improvements.

Just my experience.


By the way, Yoda. What are your thoughts on attending a TGM course? My brother in law wants me to go to one (I teach golf basics to kids at First Tee here in town) but since I am not on the PGA or a "real" golf instructor, I am kind of leary of attending.

[hg]

Do you want to do the endless belt now, or chew on this one for a while?

Yes...do the endless belt now...now that we all understand the differences between CF & CP...which does not change the fact that there are forces acting...just definitions to clarify.

[golf_sceptic]

now that we all understand the differences between CF & CP...which does not change the fact that there are forces acting...just definitions to clarify

Got it in one! But the next time somebody claims centrifugal
force powers anything you'll know what to say. It doesn't!

The endless belt...

I refer here only to a little video that seems to pop up regularly.
It shows a model held in somebody's hand with
the handle being turned and a series of little golf clubs
moving along a straight section (of belt) and then around
a curved section (of belt). The commentator points out how
the little clubs whiz around the curved part.

Now that's fine as far as it goes. Unfortunately that is also
as far as the model validly goes. The little clubs do whiz
around the end. Unfortunately the model does not show how the
clubhead accelerates, or that CF throws the club out or anything
else as is frequently claimed.

For reference, here is what happens in the model.
Firstly, for simplicity we assume that the handle is
being turned at a constant rate. This in turn means
that all parts of the belt are moving at a constant
speed and so are the grip ends of all the little clubs.

This has three results.
1. The clubheads are moving at a constant speed whilst
the belt is on the flat.
2. The clubheads are moving at a higher but constant
speed whilst the belt is on the curve.
3. The change in speed from lower to higher happens
instantaneously (not gradually) when the belt changes
shape from straight to curved.

When the little club moves from the straight part to
the curved part there will be quite a jolt to the little
club and you would not want to try this in real life.
It would be a bit like going over the pulleys when riding
on a chairlift in the snow. In the model this is disguised
by the general jerkiness involved in winding the handle
whilst the model is held in the hand.

As for my tone on arrival here, have a look at what you
were saying in this thread prior to my contribution especially
the "centrifugally powered golf swing" snideness and the
person who decided to visit ISG to "tell us off", followed
after my post by the mockery about the "force with no name".

I make a contribution and get a straw man argument
from one of the most knowledgeable teachers on the planet.

It cuts both ways fellas. Fair's fair!

[annikan skywalker]

What is the name of the Force with no name?..no mockery...label it please.. we would like to learn for we are just humble peasants ..no need to be defensive..just name the force that is opposite of Centrepetal Force....or isn't there a force...I would agree that the force that pulls the string in an angular motion IS Centrepetal Force..then what force pulls the string outward or lengthwise?..or is this just an accident?....What makes the radius of gyration move from smaller to larger?.... We just would like to know without the TGM spin on it!!!

[golf_sceptic]

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.