Swing Path

[iacas]

Angles and Physics?

Quick question for y'all.

Swing path and clubface angle affect the flight of a golf ball. Obviously.

Physics says that a ball leaves a clubface perpendicular to the clubface - thus providing the initial starting direction of the ball.

If the swing path is outside-to-in relative to that clubface angle, it fades from there. If it's in-to-out, it draws. If it's square, it goes straight.

For example, a block - a shot straight right - is hit with an inside-to-out swing path and a clubface square to the swing path (but open relative to the target line). It starts right (the club face is open relative to the target) and doesn't curve (club face square to swing path).

But, oddly, there are a lot of people (and a lot of articles online) that say that the swing path affects the initial direction the ball goes and the clubface angle affects the spin (and thus the curve). That doesn't make sense. Not in any world governed by physics like we have on earth.

Imagine in your mind aiming your driver at a target, hitting the ball with a clubface square to that target, but cutting across the ball 45 degrees outside to in. Does the ball start 45 degrees left and then go straight? No - it starts straight (for 50 feet or so) and then slices like crazy.

Why then are there so many articles that say the swing path determines the initial direction?? That just doesn't make sense.

What do y'all think?

[Hifade]

That hurts my head thinking of all that...instead Path Pro baby. :vava:

 

 

 

Quick question for y'all.

 

Swing path and clubface angle affect the flight of a golf ball. Obviously.

 

Physics says that a ball leaves a clubface perpendicular to the clubface - thus providing the initial starting direction of the ball.

 

If the swing path is outside-to-in relative to that clubface angle, it fades from there. If it's in-to-out, it draws. If it's square, it goes straight.

 

For example, a block - a shot straight right - is hit with an inside-to-out swing path and a clubface square to the swing path (but open relative to the target line). It starts right (the club face is open relative to the target) and doesn't curve (club face square to swing path).

 

But, oddly, there are a lot of people (and a lot of articles online) that say that the swing path affects the initial direction the ball goes and the clubface angle affects the spin (and thus the curve). That doesn't make sense. Not in any world governed by physics like we have on earth.

 

Imagine in your mind aiming your driver at a target, hitting the ball with a clubface square to that target, but cutting across the ball 45 degrees outside to in. Does the ball start 45 degrees left and then go straight? No - it starts straight (for 50 feet or so) and then slices like crazy.

 

Why then are there so many articles that say the swing path determines the initial direction?? That just doesn't make sense.

 

What do y'all think?

15913[/snapback]

[Gxgolfer]

Quick question for y'all.

 

Swing path and clubface angle affect the flight of a golf ball. Obviously.

 

Physics says that a ball leaves a clubface perpendicular to the clubface - thus providing the initial starting direction of the ball.

 

If the swing path is outside-to-in relative to that clubface angle, it fades from there. If it's in-to-out, it draws. If it's square, it goes straight.

 

For example, a block - a shot straight right - is hit with an inside-to-out swing path and a clubface square to the swing path (but open relative to the target line). It starts right (the club face is open relative to the target) and doesn't curve (club face square to swing path).

 

But, oddly, there are a lot of people (and a lot of articles online) that say that the swing path affects the initial direction the ball goes and the clubface angle affects the spin (and thus the curve). That doesn't make sense. Not in any world governed by physics like we have on earth.

 

Imagine in your mind aiming your driver at a target, hitting the ball with a clubface square to that target, but cutting across the ball 45 degrees outside to in. Does the ball start 45 degrees left and then go straight? No - it starts straight (for 50 feet or so) and then slices like crazy.

 

Why then are there so many articles that say the swing path determines the initial direction?? That just doesn't make sense.

 

What do y'all think?

15913[/snapback]

 

 

I tend to visualize it as a tennis swing. I'm pretty sure a tennis ball has longer contact with a raquet face though but, the principles are the same. Topspin, underspin, cut, and slice. The path of your raquet engraines your swing and pattern/shape of your shot. So the physics of the golf swing is dependant upon good fundamentals which promotes proper path and face contact.

 

I've taken more than a few lessons with a top 100 instructor, Rich Rhoads. His method teaches alot about understanding club and face contact. 9/10 times, he can hit hosel rocket, in the intended direction he wants, to illustrate his points about the physics of club and ball contact.

[iacas]

I tend to visualize it as a tennis swing.  I'm pretty sure a tennis ball has longer contact with a raquet face though but, the principles are the same.  Topspin, underspin, cut, and slice.  The path of your raquet engraines your swing and pattern/shape of your shot.  So the physics of the golf swing is dependant upon good fundamentals which promotes proper path and face contact.

 

I've taken more than a few lessons with a top 100 instructor, Rich Rhoads.  His method teaches alot about understanding club and face contact.  9/10 times, he can hit hosel rocket, in the intended direction he wants, to illustrate his points about the physics of club and ball contact.

15942[/snapback]

And that's probably a good way to look at it. So to hit a topsin shot in tennis, the face of the racket is mainly square, and the swing is low to high to generate the spin. The ball leaves roughly perpendicular to the face of the racket.

 

Which makes sense to me.

 

But all these articles you see online talk about how the swing path affects the initial direction.

[Gxgolfer]

I tend to visualize it as a tennis swing.  I'm pretty sure a tennis ball has longer contact with a raquet face though but, the principles are the same.  Topspin, underspin, cut, and slice.  The path of your raquet engraines your swing and pattern/shape of your shot.  So the physics of the golf swing is dependant upon good fundamentals which promotes proper path and face contact.

 

I've taken more than a few lessons with a top 100 instructor, Rich Rhoads.  His method teaches alot about understanding club and face contact.  9/10 times, he can hit hosel rocket, in the intended direction he wants, to illustrate his points about the physics of club and ball contact.

15942[/snapback]

And that's probably a good way to look at it. So to hit a topsin shot in tennis, the face of the racket is mainly square, and the swing is low to high to generate the spin. The ball leaves roughly perpendicular to the face of the racket.

 

Which makes sense to me.

 

But all these articles you see online talk about how the swing path affects the initial direction.

15945[/snapback]

 

 

That would be because your backswing is supposed to be a mirror of your follow through. Since the swing is initiated backwards, that's suppposed to be what you visualize first. Plus unless your Tiger Woods, you can't control your downswing, that's supposed to be physics and when people fight it, then they get into trouble...

[iacas]

That would be because your backswing is supposed to be a mirror of your follow through.  Since the swing is initiated backwards, that's suppposed to be what you visualize first.  Plus unless your Tiger Woods, you can't control your downswing, that's supposed to be physics and when people fight it, then they get into trouble...

15947[/snapback]

I mean no offense by this, but this really isn't on topic. Perhaps it's my fault...

 

I'm asking a question that, restated, can be put this way: what affects the initial direction a shot travels: where the club face is pointed at contact or the swing path?

 

Physics, common sense, and hitting a few thousand balls tell me it's the angle of the club face. But lots of articles I've read say it's the swing path.

[Gxgolfer]

That would be because your backswing is supposed to be a mirror of your follow through.  Since the swing is initiated backwards, that's suppposed to be what you visualize first.  Plus unless your Tiger Woods, you can't control your downswing, that's supposed to be physics and when people fight it, then they get into trouble...

15947[/snapback]

I mean no offense by this, but this really isn't on topic. Perhaps it's my fault...

 

I'm asking a question that, restated, can be put this way: what affects the initial direction a shot travels: where the club face is pointed at contact or the swing path?

 

Physics, common sense, and hitting a few thousand balls tell me it's the angle of the club face. But lots of articles I've read say it's the swing path.

15950[/snapback]

 

 

Physics is absolute. Working a ball is based upon physics. Getting the clubhead to achieve the desired point of contact is the part of the swing mechanics. Lots of Pros have unique swings but it in the contact zone they all appear near the same or identical. More to your question is how to teach someone to achieve a repeatable swing by getting the clubhead in the right impact position consistently. In reality, the swing shouldn't change if you want to hit a hook or a fade. The club head is either hooded or the face laid open depending upon desired shot. You can also adjust your stance to increase or decrease this effect and depending upon how the ball lies.

 

Come on guys, this is a good topic, I know there are other here who will chime in...

[iacas]

Physics is absolute.  Working a ball is based upon physics.  Getting the  clubhead to achieve the desired point of contact is the part of the swing mechanics.  Lots of Pros have unique swings but it in the contact zone they all appear near the same or identical.  More to your question is how to teach someone to achieve a repeatable swing by getting the clubhead in the right impact position consistently.  In reality, the swing shouldn't change if you want to hit a hook or a fade.  The club head is either hooded or the face laid open depending upon desired shot.  You can also adjust your stance to increase or decrease this effect and depending upon how the ball lies.

 

Come on guys, this is a good topic, I know there are other here who will chime in...

15965[/snapback]

That's still not really what I'm after here... That is not "more to my question" but is instead away from my question.

 

Uhh, so never mind.

[MrBig]

iacas,

 

I'm no scientist, but I did stay at a holiday inn so let me give this a try...

 

The trajectory or flight path of a golf ball is determined by spin. While its true path initiates the direction a ball will start spin ultimately controls flight. For instance, fundamentally poor slow swingers are recommended to use higher lofted drivers. This promotes more backspin and consequently higher and straighter ball flight. If your face angle is extreme it can over power your path. In my swing I have a tendency to hit what appear to be pull hooks on occasion. My fear was that I was coming over the top, the reality was I was smothering shots with an extremely closed face at impact. The trick is balancing backspin to side spin and your shot will travel more closely to your path. Hope this helps...

 

G

[iacas]

iacas,

 

I'm no scientist, but I did stay at a holiday inn so let me give this a try...

 

The trajectory or flight path of a golf ball is determined by spin. While its true path initiates the direction a ball will start spin ultimately controls flight. For instance, fundamentally poor slow swingers are recommended to use higher lofted drivers. This promotes more backspin and consequently higher and straighter ball flight. If your face angle is extreme it can over power your path. In my swing I have a tendency to hit what appear to be pull hooks on occasion. My fear was that I was coming over the top, the reality was I was smothering shots with an extremely closed face at impact. The trick is balancing backspin to side spin and your shot will travel more closely to your path. Hope this helps...

 

G

16112[/snapback]

No, never mind, I must not be stating things clearly, because the responses I'm getting aren't really what I'm after at all.

 

Basically, it boils down to this: what determines initial direction of the ball (i.e. the first 10% of a ball's flight): clubface angle or swing path?

 

Most articles argue that it's swing path, but that doesn't make sense to me (or anyone who's studied physics), and I say that it's clubface angle that determines initial direction.

[nearfall152]

No, never mind, I must not be stating things clearly, because the responses I'm getting aren't really what I'm after at all.

 

Basically, it boils down to this: what determines initial direction of the ball (i.e. the first 10% of a ball's flight): clubface angle or swing path?

 

Most articles argue that it's swing path, but that doesn't make sense to me (or anyone who's studied physics), and I say that it's clubface angle that determines initial direction.

16132[/snapback]

 

It is true that the center of mass of a ball will rebound from the face of the club normal (90*) to the face. What I think you are confused with is a non issue...the 'swing path' as you describe it is the method that the face of the club is delivered to the ball. The orientation of the face at impact decides the direction of the ball, naturally, but the orientation of the face at impact depends upon the 'swing path' argument you have described. Its a chicken / egg kind of thing.

 

Don't confuse the impact position with *anything* that happens after that. There is quite a bit going on in a short amount of time that the ball is on the face that also alters the launch parameters. Flight path is a complicated equation; a simplified model can be constructed using several variables and partial differential equations. Even the most compilcated equations modeling ball flight don't take into very real non-conservative forces that change things quite a bit.

 

I have advanced degrees in physics and math, and I've fiddle-faddled with these models quite a bit over the last few years. It's pretty fun, and I do have models if you're interested (or if you're having trouble sleeping :vava: )

 

It's good to ask questions about this stuff, it's natural. But some of these guys were trying to answer you before, and you got a little frustrated with them...they were just trying to help.

 

The best bet is if you want to figure something out is to ask questions (which you did) and listen to what others have to say. If you think its crap that they're saying, then either go ask someone else or figure it out for yourself. Design your own experiments, obtain your own results, form your own opinion. Don't believe a word that I have to say unless the evidence makes sense to you. :D :cheesy:

[iacas]

It is true that the center of mass of a ball will rebound from the face of the club normal (90*) to the face.

 

That's all I'm asking. Yet - as I've now said a few times - if you read articles, they suggest that the SWING PATH determines the initial direction of the shot.

 

What I think you are confused with is a non issue...

I'm not the one that's confused. I'm asking why so many articles out there get this so wrong.

 

the 'swing path' as you describe it is the method that the face of the club is delivered to the ball.  The orientation of the face at impact decides the direction of the ball, naturally, but the orientation of the face at impact depends upon the 'swing path' argument you have described.  Its a chicken / egg kind of thing.

I don't believe it's a chicken/egg thing at all. They combine to work as... whatever.

 

If I deliver a clubface 5 degrees open to the target line but 10 degrees from the inside (swing path), the shot will start right of target due to the open clubface and then draw back because, the swing path was still from the inside relative to the clubface.

 

But several articles would suggest that it's the swing path that starts the ball to the right, and the fact that the club face is closed (relative to the swing path) that draws it back. The latter part I have no problem with - that's fine. It's the first part - that the swing path is what starts the ball right. Which is not and cannot be true.

 

Don't confuse the impact position with *anything* that happens after that.

I assure you I'm not.

 

It's good to ask questions about this stuff, it's natural.  But some of these guys were trying to answer you before, and you got a little frustrated with them...they were just trying to help.

No, I was frustrated with my apparent inability to properly communicate my question, which is simply this: why do so many articles get it so wrong? Even your response leads me to believe you've not understood what I'm asking (which is not the same thing as not understanding the physics of the whole thing).

 

For example:

 

http://www.drgolf.org/new_page_4.htm sez:

"Initial ball flight direction is governed by the direction that the clubhead is traveling at impact."

 

http://www.golftrainingstuff.com/golf_ball_flight_laws.html sez:

"Path of the club - Greatest influence on ball-flight: Initial Direction"

 

http://www.pga.com/improve/tips/techniques...liott100504.cfm sez:

"SWING PATH* Swing path is the direction the club moves from the top of you back swing down through impact. Your swing path determines what direction your ball begins. (I.e. push, pull, straight) "

 

And so on. All these articles reference swing path as having the greatest influence on the initial direction of the ball, but that's clearly not the case from a physics standpoint. Why is this incorrect information so popular? So widely believed?

 

As I've said, if I swing across the back of the ball, outside to in thirty degrees, with a clubface square to the target line, the ball doesn't start 30 degrees left. It starts straight and slices like crazy (because, relative to that swing path, the face was open).

 

The way these articles are worded, they'd have you believe that it starts left. Why have they got it all so wrong?

 

Perhaps now I've stated my question clearly. I apologize if I've failed to do so yet (or if I continue to fail to do so).

[Gxgolfer]

Personally,

 

I really think they use the term swing path to help people visualize the golf swing. Its like teaching by feel vs mechanical. Alot people will get a glazed over look over their face when reading these posts...I think they are more feel oriented... :vava:

[Golfchicago]

I think the slower you swing the clubhead affects direction more and the faster you swing then path affects the initial direction. For example in putting, clubhead is more important for initial direction. In a full swing club path is more important. Im not into the science end to be able to eplain why, but I do know it works and that is all the proof I need.

[Zach Heusser]

I agree with what chicago said. The path starts it, and the face curves it in most cases. But in severe cases the face can overrule the path. Especially in slower swing speeds, or with very closed or open club faces.

Zach

[MrParr1Noid]

And to think, when I started playing this game, guys were telling me it's just golf, hit the ball, this isn't rocket science. And now I've found out the real truth, golf really is rocket science. :vava:

[MrBig]

'noid,

 

Anything to squeeze out that extra yard, foot, inch... A classic case of paralysis by analysis.

 

G

[Letitroll98]

What nearfall152 is trying to tell you is that the physics involved is a vector equation with variables being relative velocity, coefficient of friction, compression factors of both ball and clubface, launch angles, and several other factors that I can't think of right now. The point being all of these factors combine to create a ball flight.

 

However, from anecdotal data (stuff you can see from common sense) we can draw general conclusions. You can do this from working backwards from the ball flight, i.e. a dead straight pull would be an outside in swing path with a club face 90 degrees to the swing path, a pull/ slice would be the same thing with an open clubface. So for this example, there would be coefficient of friction with an open clubface as the ball would slide x amount across the clubface causing it to start out a bit more right, as in your example.

 

So the reason you're not getting the answer you want is there isn't one that fits the parameters of your question. Depending on how much the path varies from on line and how much the clubface varies from neutral, one of these factors become dominant. As mentioned above, perhaps in a really fast swing, path is most important, or in a slower swing clubface angle dominates. But they always work together in some fashion.

[juststeve]

John Jacobs taught that the initial direction of the ball was controlled by path and curavure by club face angle. Whether he was right or not as a matter of physics, that mode of thought works for correcting ball flight, so I use it.

 

Steve

[clutchfan]

I believe swing path effects the initial direction of ball flight and face angle relative to path dictates curve

[TCWhite]

I agree clutchfan. The simple answer here is that the ball sticks to the clubhead for a period of time, therefore it travels in the same direction as the clubhead after it leaves. As the ball springs off, lateral spin is imparted if the clubface is not perpendicular to the path and causes it to curve.

[kebeal]

"2-D-0 DIRECTIONAL FACTORS

 

Another need for a "perfect circle" motion is for directional control. If the clubface is maintaining a constant relationship to the radius of it's rotation- whether face is open, closed, or square- then the direction imparted at any one point of the arc will always be the same for "centered" (sweet spot) impact.

 

The angular motion in a golf stroke is compounded by it's dual centers. One center is for the clubhead as a whole, and the other center is for the clubface position. Deviation in horizontal hinge action during impact can produce considerable variation in direction but little change in trajectory. Deviations in vertical hinge action during impact can produce great variation in trajectory but little variation in direction. Angled hinge action on the flatter planes approaches the horizontal hinge characteristics and as the plane steepens it moves toward virtical hinge characteristics.

 

The direction of the ball will always be practically at right angles to the clubface and square to the leading edge of the clubface at seperation, unless there is enough time and speed for the venturi effect to alter it when scattered vectors have introduced a non-vertical spin. That is- the flight path will bend away from the flight line. Tilting the leading edge changes the clubface alignment. Up- to the left. Down- to the right. Merley deviating from the address plane angle will do this by tilting the clubshaft. And from driver to putter, directional deviation can be diagnostic:

1. Shoulder turn closes the clubface - the pull

2. Not extending the right arm opens the clubface - the push

3. Bending the left wrist makes clubface alignment erratic

 

The direction of the ball will be the resultant of the vectors of the forces acting on the ball, unless all the forced can be focused on one line. Then directional control would be stabilized and, in addition, the ball would be propelled by the sum of the forces acting on it, instead of themuch smaller resultant force of scattered vectors. The vector of the spin-producing force cannot be brought into alignment or there would loss of altitude control as well as spin control. But the spin can be produced on the plane of the actual line of flight and thus exert no interference with the alignment of the forces."

 

- The Golfing Machine by Homer Kelley

 

 

HINGE ACTIONS: (motion of the arms and hands through impact)

 

Horizontal - closing only action (example: an ordinary door)

Vertical - laying back only (example: a pendulum)

Angled - closing and layback (example: a canoeist paddle)

 

Remeber, all three are performed on an inclined plane (/) during the golf stroke.

 

In other words clubface provides inital direction, while clubhead path gives the ball it's spin or direction.

[bigpopper81]

Swingpath determines initial direction. Clubface determines spin.

[lars]

If looking for a scientific detail of this phenomenon, you can check

 

 

 

Science and Golf III - Proceedings of the World Scientific Congress of Golf

 

Chapter 67. The Initial Trajectory Plane After Ball Impact

K. Miura & F. Sato

 

 

 

or here http://www.iop.org/EJ/abstract/0034-4885/66/2/202

 

 

 

or The Physics of Golf

by Theodore P. Jorgensen.

 

 

 

hope this helps.

 

 

 

L

[hayam]

I think another way to answer your question is

 

Many people think the bottom of the swing is bottom of the spine. its when your leading arms is perpendicular to the ground.

 

Many people think the ball should be impact right at the back of the ball. It should leave the clubface square to the target.

 

Many people think Swing path will control the spin. its actually the clubface at impact you might come in out side in with a bend left wrist that closes the face at impact and you will hit a pull hook. This can be confusing, but its really related to the above. and what actually you think happened and actually happened is different.

 

IT could be many things for example in certain swing type , the more u move the ball up the stance, the more it draws , certain type the other way round , this highly depends on your grip setup and hand position at setup and whether you are swinging to close during impact. ( horizontal hinge)

 

But definitely Geometry and physics can explain everything. Just that i personally could not think there is a easy way to explain this. I learn all this from The Golfing Machine, its not a book about swing this way, its a book about what can work and cannot work in a swing. Maybe not 100% correct , but closest 100% I ever heard, found or smelled. It certainly makes a golf swing less Mysterious.

[KeilwerthSX90R]

I haven't read the last few replies so I hope I'm not covering the same ground but . . .

 

Your swing path determines the initial direction of the ball and the angle of the club face dictates the spin.

 

So an outside-in path with an open face would start left and slice back.

 

The initial direction will be perpendicular to the face but in the direction the force is being applied - thus the swing path.

[bethpage16]

It is true that the center of mass of a ball will rebound from the face of the club normal (90*) to the face.

 

That's all I'm asking. Yet - as I've now said a few times - if you read articles, they suggest that the SWING PATH determines the initial direction of the shot.

 

What I think you are confused with is a non issue...

I'm not the one that's confused. I'm asking why so many articles out there get this so wrong.

 

the 'swing path' as you describe it is the method that the face of the club is delivered to the ball.  The orientation of the face at impact decides the direction of the ball, naturally, but the orientation of the face at impact depends upon the 'swing path' argument you have described.  Its a chicken / egg kind of thing.

I don't believe it's a chicken/egg thing at all. They combine to work as... whatever.

 

If I deliver a clubface 5 degrees open to the target line but 10 degrees from the inside (swing path), the shot will start right of target due to the open clubface and then draw back because, the swing path was still from the inside relative to the clubface.

 

But several articles would suggest that it's the swing path that starts the ball to the right, and the fact that the club face is closed (relative to the swing path) that draws it back. The latter part I have no problem with - that's fine. It's the first part - that the swing path is what starts the ball right. Which is not and cannot be true.

 

Don't confuse the impact position with *anything* that happens after that.

I assure you I'm not.

 

It's good to ask questions about this stuff, it's natural.  But some of these guys were trying to answer you before, and you got a little frustrated with them...they were just trying to help.

No, I was frustrated with my apparent inability to properly communicate my question, which is simply this: why do so many articles get it so wrong? Even your response leads me to believe you've not understood what I'm asking (which is not the same thing as not understanding the physics of the whole thing).

 

For example:

 

http://www.drgolf.org/new_page_4.htm sez:

"Initial ball flight direction is governed by the direction that the clubhead is traveling at impact."

 

http://www.golftrainingstuff.com/golf_ball_flight_laws.html sez:

"Path of the club - Greatest influence on ball-flight: Initial Direction"

 

http://www.pga.com/improve/tips/techniques...liott100504.cfm sez:

"SWING PATH* Swing path is the direction the club moves from the top of you back swing down through impact. Your swing path determines what direction your ball begins. (I.e. push, pull, straight) "

 

And so on. All these articles reference swing path as having the greatest influence on the initial direction of the ball, but that's clearly not the case from a physics standpoint. Why is this incorrect information so popular? So widely believed?

 

As I've said, if I swing across the back of the ball, outside to in thirty degrees, with a clubface square to the target line, the ball doesn't start 30 degrees left. It starts straight and slices like crazy (because, relative to that swing path, the face was open).

 

The way these articles are worded, they'd have you believe that it starts left. Why have they got it all so wrong?

 

Perhaps now I've stated my question clearly. I apologize if I've failed to do so yet (or if I continue to fail to do so).

 

 

your use of physics (or should i say the laws of "dynamics" - the study of causes of motion) is limited. Let me illustrate

 

a stationary club - a ball dropped at the centre should come back on the same path. however, if the same ball approaches at a 45* angle to the club face and assuming no energy loss), it will leave the club face 45* in the opposite direction.

 

Why does that happen? without trying to give you a class in physics, you will remember that

 

Force = mass * (acceleration) = momentum (mass * velocity) * velocity

 

mass is one dimensional (scalar). velocity is a vector (it has an x and y component). for ease, think y has the distance the ball travels from the tee, and x has the distance it travels from the point it would have stopped if there was no spin imparted to the club (i.e. if it had only moved in a straight line). To illustrate better, imagine that if there was no spin imparted, it would have travelled 250 yards striaght at an angle so that it is 25 yards offcentre. y = 250 yards.

 

Momentum is needed to move any stationary object. when the ball is on the tee - its not moving, its velocity is zero. you need force to change the momentum, thats what the club does. it imparts momentum to the ball IN THE DIRECTION THE CLUB IS SWINGING. thats what determines the initial swing path. at this point the Y component is overpowering. Note the ball starts moving to the centre immediately, but given that 25 yards offcentre in the example is 1/10 of the y component, you cannot notice it as much, thats it why it looks like going in the direction the club is swinging. when you reach the 250 yards mark, it has drawn back to the centre by 25 yards, you start noticing the spin. towards the end, the y component and x component are almost equal and you see the big swing in the ball.

 

But now the club face comes into play, if you hit the ball with the clubface at an angle, the momentum on the ball has a component that drives the ball back to the centre. the distance it moves back to the centre depends on the other component which is much much lower than the forward motion.

 

Note the ball trys to move to the centre immediately, but given that 25 yards offcentre in the example is 1/10 of the y component, the y component effect is overpowering, you cannot notice the lateral moment initially. thats why the ball PRIMARILY goes in the direction the club is swinging. when you reach the 250 yards mark, it has drawn back to the centre by 25 yards, you start noticing the spin. towards the end, the y component and x component are almost equal and you see the big swing in the ball.

 

 

its tough to explain the dynamics in a note, but it should give you an idea.

 

 

now the balls that start straight and then slice, or the ball that starts straight and then hooks etc, it all depends on the relationship of the force that provides momentum (clubhead speed) and the angle and the relevant half (right, left etc) of the clubface that makes contact with the ball.

[chris87]

bethpage, I'm not entirely sure about the physics involved in putting spin on a golf ball, but I'm positive that mass*acceleration does not equal momentum* velocity. Actually, force is the derivative of momentum, which is equal to m*a so long as the mass is constant.

[Young04]

It is true that the center of mass of a ball will rebound from the face of the club normal (90*) to the face.

 

That's all I'm asking. Yet - as I've now said a few times - if you read articles, they suggest that the SWING PATH determines the initial direction of the shot.

 

What I think you are confused with is a non issue...

I'm not the one that's confused. I'm asking why so many articles out there get this so wrong.

 

the 'swing path' as you describe it is the method that the face of the club is delivered to the ball.  The orientation of the face at impact decides the direction of the ball, naturally, but the orientation of the face at impact depends upon the 'swing path' argument you have described.  Its a chicken / egg kind of thing.

I don't believe it's a chicken/egg thing at all. They combine to work as... whatever.

 

If I deliver a clubface 5 degrees open to the target line but 10 degrees from the inside (swing path), the shot will start right of target due to the open clubface and then draw back because, the swing path was still from the inside relative to the clubface.

 

But several articles would suggest that it's the swing path that starts the ball to the right, and the fact that the club face is closed (relative to the swing path) that draws it back. The latter part I have no problem with - that's fine. It's the first part - that the swing path is what starts the ball right. Which is not and cannot be true.

 

Don't confuse the impact position with *anything* that happens after that.

I assure you I'm not.

 

It's good to ask questions about this stuff, it's natural.  But some of these guys were trying to answer you before, and you got a little frustrated with them...they were just trying to help.

No, I was frustrated with my apparent inability to properly communicate my question, which is simply this: why do so many articles get it so wrong? Even your response leads me to believe you've not understood what I'm asking (which is not the same thing as not understanding the physics of the whole thing).

 

For example:

 

http://www.drgolf.org/new_page_4.htm sez:

"Initial ball flight direction is governed by the direction that the clubhead is traveling at impact."

 

http://www.golftrainingstuff.com/golf_ball_flight_laws.html sez:

"Path of the club - Greatest influence on ball-flight: Initial Direction"

 

http://www.pga.com/improve/tips/techniques...liott100504.cfm sez:

"SWING PATH* Swing path is the direction the club moves from the top of you back swing down through impact. Your swing path determines what direction your ball begins. (I.e. push, pull, straight) "

 

And so on. All these articles reference swing path as having the greatest influence on the initial direction of the ball, but that's clearly not the case from a physics standpoint. Why is this incorrect information so popular? So widely believed?

 

As I've said, if I swing across the back of the ball, outside to in thirty degrees, with a clubface square to the target line, the ball doesn't start 30 degrees left. It starts straight and slices like crazy (because, relative to that swing path, the face was open).

 

The way these articles are worded, they'd have you believe that it starts left. Why have they got it all so wrong?

 

Perhaps now I've stated my question clearly. I apologize if I've failed to do so yet (or if I continue to fail to do so).

 

 

your use of physics (or should i say the laws of "dynamics" - the study of causes of motion) is limited. Let me illustrate

 

a stationary club - a ball dropped at the centre should come back on the same path. however, if the same ball approaches at a 45* angle to the club face and assuming no energy loss), it will leave the club face 45* in the opposite direction.

 

Why does that happen? without trying to give you a class in physics, you will remember that

 

Force = mass * (acceleration) = momentum (mass * velocity) * velocity

 

mass is one dimensional (scalar). velocity is a vector (it has an x and y component). for ease, think y has the distance the ball travels from the tee, and x has the distance it travels from the point it would have stopped if there was no spin imparted to the club (i.e. if it had only moved in a straight line). To illustrate better, imagine that if there was no spin imparted, it would have travelled 250 yards striaght at an angle so that it is 25 yards offcentre. y = 250 yards.

 

Momentum is needed to move any stationary object. when the ball is on the tee - its not moving, its velocity is zero. you need force to change the momentum, thats what the club does. it imparts momentum to the ball IN THE DIRECTION THE CLUB IS SWINGING. thats what determines the initial swing path. at this point the Y component is overpowering. Note the ball starts moving to the centre immediately, but given that 25 yards offcentre in the example is 1/10 of the y component, you cannot notice it as much, thats it why it looks like going in the direction the club is swinging. when you reach the 250 yards mark, it has drawn back to the centre by 25 yards, you start noticing the spin. towards the end, the y component and x component are almost equal and you see the big swing in the ball.

 

But now the club face comes into play, if you hit the ball with the clubface at an angle, the momentum on the ball has a component that drives the ball back to the centre. the distance it moves back to the centre depends on the other component which is much much lower than the forward motion.

 

Note the ball trys to move to the centre immediately, but given that 25 yards offcentre in the example is 1/10 of the y component, the y component effect is overpowering, you cannot notice the lateral moment initially. thats why the ball PRIMARILY goes in the direction the club is swinging. when you reach the 250 yards mark, it has drawn back to the centre by 25 yards, you start noticing the spin. towards the end, the y component and x component are almost equal and you see the big swing in the ball.

 

 

its tough to explain the dynamics in a note, but it should give you an idea.

 

 

now the balls that start straight and then slice, or the ball that starts straight and then hooks etc, it all depends on the relationship of the force that provides momentum (clubhead speed) and the angle and the relevant half (right, left etc) of the clubface that makes contact with the ball.

 

sometimes, you just need to hit the ball :-) you over-thunk it. even for a usually overly analytical lawyer like myself.

 

i'm a little unclear on why this issue isn't more clear...you can figure this out by your own experimentation. how would one hit a push-draw? you swing from the inside (swing path creates initial ball path), with a square to slightly closed face. the converse is true for hitting a pull fade.

 

by the original poster's theory, if you're going to hit a push-draw, you have to leave the club face open? doesn't make sense to me.

 

that said, an extremely open or an extremely closed face can overcome a counteracting swing path, i.e., if you hit from the inside, but slam the club shut at impact and smother the ball, it won't start right - it'll likely come out looking like a pull hook (or a straight snap hook at best).

[Pole_Position]

OK, taking out the fact that the club head is moving on an arc and is rotating relative to the ball and has loft (and sometimes bulge and roll) and the ball compresses and club head speed all the other things that muddy the equation, in my mind two things are clear:

 

1. At the critical moment, if the club face is square to the club head path then club head path is the sole determinant of the balls direction.

 

2. The club face being open or closed relative to club head path is the only thing that will impart side spin on the ball (assuming a "sweet spot" hit and taking gear effect out of the equation).

 

The question is: does the club face being open or closed ALSO influence direction? Of course it does (IMO). The best way to view this would be to flip the open club face 90* and turn it into loft (on an iron, for instance). Loft on an iron influences how far forward (horizontal distance) and the launch angle (the direction the ball launches vertically or relative to the ground). Hit a two iron and the horizontal component has a larger influence then the vertical component. Hit a SW and the vertical component probably rules. If the angle of loft didn't influence the ball's direction then the launch angle would be the same regardless of loft.

 

With irons you're talking lofts in the range of 20* - 60*. Going back to the open/closed club face, with most golfers you're talking about 1* to 8* of open/closed (at least from what I've seen on launch monitors). I also see about 1* - 11* swing path deviation.

 

My conclusion is this:

 

BOTH club path and face angle influence ball direction. The amount each influences direction depends on its deviation. The club face being open or closed relative to club head path is the only thing that will impart side spin on the ball (taking gear effect out of the equation).

 

Another way to say it:

 

Club path ALWAYS influences direction.

 

Club face angle ALWAYS influences side spin and CAN influence direction (if it's not square).