CP/CF release

[mandrin]

In golf one frequently looks for ways to convey concepts with images or expressions. “CP/CF release” is a part of this lot.

CP/CF release implies a centrifugal or a centripetal force acting on the club through the release phase of the club through the bottom part of the swing. In either swinging or hitting this is not the case. The only radial force playing a significant role in the release is the centripetal force acting on the hands/arms. It is much smaller than the radial forces associated with the club yet produces the most significant release torque.

Old timer pro Roberto Vincenzo felt that he hit the ball with his stomach. If that were the case than golfers would have all very sore stomachs for sure. Yet quit likely some immediately feel what is being conveyed and they are most likely martial arts adepts. So golf terms are not necessarily describing an objective truth but often try to concoct an image, a feeling or both with which a golfer can identify.

 

[mandrin]

There was a post asking for a some simple explanation of centripetal and centrifugal forces.

Prepared some response but the post has disappeared. Anyhow will post it nevertheless.

Imagine a small point mass M attached with a spring, having neutral length L1, to a fixed center O.

When the mass starts rotating around O we know from experience that the spring stretches to a slightly longer length L2.

Therefore the mass M exerts a force on the spring, given by F= k (L2 - L1), where k = spring constant ....Fig2, blue vector.

Also the spring exerts hence a force on the mass M trying to pull it back toward the center......Fig2, red vector.

These two forces from a Newtonian action-reaction pair. In nature forces never exist as singles.

The red force is the centripetal force whereas the blue force is the centrifugal force.

Hence the mass M exerts a centrifugal force on the spring and the spring, being stretched, in turn generates the centripetal force acting on the mass M.

These two forces are equal in magnitude and acting in opposite directions, as is the case for all Newtonian action reaction force pairs.

Notice that both forces are acting along a line of action going through the center of rotation.

Frequently forgotten, action-reaction force pairs never act on the same object.

There are pseudo scientists who aggressively claim that centrifugal force does not exist.

However the extension of the spring makes its existence clearly evident and easily measurable.

Normally one considers centripetal force to be cause and centrifugal force to be effect.

That dividing line is very thin indeed. The description above makes centrifugal force rather appear to be cause.

 

[mgranato]

Very clear, Mandrin, thanks. I learned 3 new things and confirmed 1 old thing.

 

[cwdlaw223]

Mandrin -

What force do we feel in the downswing in our hands?

 

[ggsjpc]

Why does this make more sense to me? What am I missing?

 

[grahler]

If the mass were not attached to a spring but to a fixed arm where would it go if it became disconnected from the arm during rotation?
I don't think its straight out from center and is that significant? Also if gravity were not involved how would one accelerate the mass?
LOL I can almost relate this to golf but thank you Mandrin for providing something fun to consider.

 

[mandrin]

Mandrin -

What force do we feel in the downswing in our hands?

cwdlaw223,

I can't answer that question. Too each his own. For instance, there is a very large centrifugal force acting at the shoulder socket and wrist joint yet we are barely aware of it. It just happens too quickly.

 

[mandrin]

Why does this make more sense to me? What am I missing?

ggsjpc,

Even some scientists erroneously use the argument that centrifugal force is not real. However we are not dealing with some vague esoteric concept, but with a real tangible measurable physical quantity.

The spring is a fundamental element in all kind of scientific measuring tools to measure weight, force and acceleration. That is why I illustrated radial forces using a spring.

A spring is stretched. What action is required ? A real force. We simply can't deny something to exist which is readily measured.

 

[mandrin]

If the mass were not attached to a spring but to a fixed arm where would it go if it became disconnected from the arm during rotation?
I don't think its straight out from center and is that significant? Also if gravity were not involved how would one accelerate the mass?
LOL I can almost relate this to golf but thank you Mandrin for providing something fun to consider.

grahler,

The matter is very simple. Radial forces, such as centrifugal and centripetal forces, only exist when there is curvilinear motion. If you severe the connection between the object and the center you don't have such motion anymore and these radial forces completely disappear. Hence as soon as the connection between object and center is severed the object simple continues straight ahead, tangentially, there being no forces acting on it anymore. A mass can be accelerated by any force acting on it. Gravity is a force around in nature but is not required to accelerate a mass.

 

[grahler]

Thanks for responding.
I also get confused with radial force definition. In a bearing on a shaft industry convention is to define a radial load as perpendicular to the shaft and an axial load as parallel to the shaft. To me in a golf swing with "bearing industry" terminology the axial force is the important one. I will have to learn golf terminology LOL ty sir.

 

[TeeAce]

There are pseudo scientists who aggressively claim that centrifugal force does not exist.

However the extension of the spring makes its existence clearly evident and easily measurable.

Normally one considers centripetal force to be cause and centrifugal force to be effect.

That dividing line is very thin indeed. The description above makes centrifugal force rather appear to be cause.

Wouldn't really call them pseudo scientists, because they know what they are talking about.

Centrifugal force is not real force, because it never exists alone and there is never any force pulling that object to that direction.

So it's not real force, rather effect and opposite force for centripetal.

 

[ggsjpc]

ggsjpc,

Even some scientists erroneously use the argument that centrifugal force is not real. However we are not dealing with some vague esoteric concept, but with a real tangible measurable physical quantity.

The spring is a fundamental element in all kind of scientific measuring tools to measure weight, force and acceleration. That is why I illustrated radial forces using a spring.

A spring is stretched. What action is required ? A real force. We simply can't deny something to exist which is readily measured.

Mandrin,

Could you please explain why his explanation is incorrect. Based on what he said and my interpretation, wouldn't the measureable change in the spring be derived from the summation of the tangential forces and inertia?

 

[birly-shirly]

My understanding is that if you want to understand the terms "CP" and "CF" as they're used in relation to the release in golf, you'd be better served ignoring any scientific explanation of centrifugal or centripetal forces.

That's maybe not the most helpful terminology - but as far as I understand the way these terms (CP/CF) are actually used, they are really just labels for different patterns of movement. Trying to cross-reference these definitions to distinct physical forces at work is a red-herring.

 

[Brian Manzella]

When I name things, I think about it for a while first.

 

[cwdlaw223]

cwdlaw223,

I can't answer that question. Too each his own. For instance, there is a very large centrifugal force acting at the shoulder socket and wrist joint yet we are barely aware of it. It just happens too quickly.

My hands feel the clubhead in the downswing just as I would feel a rock on the end of a string if I twirled it around. Am I correct that what my hands feel is the intertia of the clubhead?

 

[gmbtempe]

My understanding is that if you want to understand the terms "CP" and "CF" as they're used in relation to the release in golf, you'd be better served ignoring any scientific explanation of centrifugal or centripetal forces.

That's maybe not the most helpful terminology - but as far as I understand the way these terms (CP/CF) are actually used, they are really just labels for different patterns of movement. Trying to cross-reference these definitions to distinct physical forces at work is a red-herring.

A+

 

[Brian Manzella]

When I name things, I think about it for a while first.

Like I said....

 

[mandrin]

Mandrin,

Could you please explain why his explanation is incorrect. Based on what he said and my interpretation, wouldn't the measureable change in the spring be derived from the summation of the tangential forces and inertia?

ggsjpc,

Let's make it as simple as possible

A point mass is circling with constant angular speed. Hence there is no tangential force whatsoever.

Moreover, inertia is a descriptive quality of matter, is not a force. If you still insist it to be a force than please give me its dimensions in fundamental MKS units.

Hence the two forces you refer to are non existent in our example.

Yet the spring is still stretched.

So what now?

Left with that poor centrifugal force wanting so dearly to be recognized ?

 

[drewitgolf]

Mandrin,

Would it be proper to sat...it is a rotating frame of reference as opposed to a non-rotating frame of reference?
The laws of physics are the same regardless. However, the explanation of what is going on varies.

 

[mandrin]

Centrifugal force is not real force, because it never exists alone

Are you really serious wanting to use this as an argument ?

Since this same argument can also be used for centripetal force you hence automatically claim also that centripetal force is not a real force.

TeeAce, you even put the fundamental third law of Newton in a garbage can.

TeeAce: A force is not real if it can't exist alone.
Newton : Forces always occur in pairs.
Conclusion: There are no real forces in the universe.

Newton's third law:

“Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi.”

“To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions.”