Pistol, I'm not sure I understand the question. Let me say this:
At every point in the golf swing the equations of motion apply ( F=ma and M = I alpha) These are of course three dimensional. Im mass in the parts of the system gets redistributed then that changes the moment of interia (I) in the second equation.
F (force) comes from gravity (small contribution minor really) and muscle contraction. When those force act on levers they cause Moments (M) which create rotation.
Muscles and gravity do not create central forces so as it is strictly defined in all physics/mechanics texts, COAM does not apply to the golf swing.
What about shear forces through the feet and ground Nmgolfer?
Nmgolfer whats your opinion of TPI kinmematic Sequence and K-Vest?
What about shear forces through the feet and ground Nmgolfer?
Well there are definitely shear force going on there but they arise as a reaction. Other forces (from muscles) need be reacted to the ground by way of normal and shear forces lest we land on our butt.
Still don't get where your're going with this. A diagram might help.
Originally Posted by pistol
Nmgolfer whats your opinion of TPI kinmematic Sequence and K-Vest?
I'm a bit amused by all of it. If you've read that other forum (before the Manz deleted all of my posts that is) then you already know my answer. Lots of buzz words but from my vantage... very little substance and virtually nothing that's going to help your average golfer.
Frankly its not exactly clear to me what exactly it is they are trying to sell... that is...what problem it is they are trying to solve. If its not just technology for technology sake one thing is clear... they are leaving their potential customers with mistaken impressions with regards to what is and is not happening durning the swing. I assume you are familiar with the term "snap your chain"?
I'm a bit amused by all of it. If you've read that other forum (before the Manz deleted all of my posts that is) then you already know my answer. Lots of buzz words but from my vantage... very little substance and virtually nothing that's going to help your average golfer.
Frankly its not exactly clear to me what exactly it is they are trying to sell... that is...what problem it is they are trying to solve. If its not just technology for technology sake one thing is clear... they are leaving their potential customers with mistaken impressions with regards to what is and is not happening durning the swing. I assume you are familiar with the term "snap your chain"?[/quote]
He deletes posts and contradicts himself all the time nmgolfer so its a hard read.."snap your chain" could mean anything so I don't know what he is getting at ..maybe breaking the chain on the old toilet flush mechanism..
Let me elaborate... at any given instance Gravity is actin on the mass of the golfer and some combination of the golfers muscles are contracting. If we were to take a snapshot in time and add up all of those forces vectorially it would have a manitude and direction. That force must be reacted or our body will accelerate (move) and its reacted by shear and normal forces at our feet. The shear and normal forces at our feet are "equal" but "opposite" (direction) to our muscle forces and gravity. That direction is not directed (necesarily) through the axis or center of rotation so its not a "central" force.
At issue is verbage. Conservation by definition implies: "limited supply" . When are muscles and gravity are applying forces which create momments we are increaing (or decrease) alpha or angular acceleration and conservation does not apply. Only if those forces are directed through the axis of rotation and therefore cannot create a torque are they central forces. I'm saying COAM does not apply. I'm not saying as mass gets redistributed the system won't speed up or slow down... The only way to know whats happening is by solving the equations of motion at each instant in time.
Last edited by no_mind_golfer : 10-27-2008 at 02:30 PM.
Let me elaborate... at any given instance Gravity is actin on the mass of the golfer and some combination of the golfers muscles are contracting. If we were to take a snapshot in time and add up all of those forces vectorially it would have a manitude and direction. That force must be reacted or our body will accelerate (move) and its reacted by shear and normal forces at our feet. The shear and normal forces at our feet are "equal" but "opposite" (direction) to our muscle forces and gravity. That direction is not directed (necesarily) through the axis or center of rotation so its not a "central" force.
At issue is verbage. Conservation by definition implies: "limited supply" . When are muscles and gravity are applying forces which create momments we are increaing (or decrease) alpha or angular acceleration and conservation does not apply. Only if those forces are directed through the axis of rotation and therefore cannot create a torque are they central forces. I'm saying COAM does not apply. I'm not saying as mass gets redistributed the system won't speed up or slow down... The only way to know whats happening is by solving the equations of motion at each instant in time.
No mind golfer my appologies to you,
your very knowlegeable and I hope you except my apology,
And what if you can measure motion at instant in time.
this can be done you can measure each segment speeding up and decelerating.
if your only applying coam from the spine to the hands then can coam be applied?
Let me elaborate... at any given instance Gravity is actin on the mass of the golfer and some combination of the golfers muscles are contracting. If we were to take a snapshot in time and add up all of those forces vectorially it would have a manitude and direction. That force must be reacted or our body will accelerate (move) and its reacted by shear and normal forces at our feet. The shear and normal forces at our feet are "equal" but "opposite" (direction) to our muscle forces and gravity. That direction is not directed (necesarily) through the axis or center of rotation so its not a "central" force.
At issue is verbage. Conservation by definition implies: "limited supply" . When are muscles and gravity are applying forces which create momments we are increaing (or decrease) alpha or angular acceleration and conservation does not apply. Only if those forces are directed through the axis of rotation and therefore cannot create a torque are they central forces. I'm saying COAM does not apply. I'm not saying as mass gets redistributed the system won't speed up or slow down... The only way to know whats happening is by solving the equations of motion at each instant in time.
In post#22 of this thread I got the impression that you disagreed with my initial post. After reading this post- it appears that we are on the same thought process. It appears to me that your 1st paragraph here is similar to what I said in item #1 of my post and your second paragraph is similar to what I said in item #2 of my post.
In summary, of course strictly speaking conservation of angular momentum does not exist in the golf swing as it is not a closed system and we are adding energy to it. However, that doesn't mean that changes in distribution of mass doesn't affect the rotational speed as described in the conservation of angular momentum formula.
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In post#22 of this thread I got the impression that you disagreed with my initial post. After reading this post- it appears that we are on the same thought process. It appears to me that your 1st paragraph here is similar to what I said in item #1 of my post and your second paragraph is similar to what I said in item #2 of my post.
In summary, of course strictly speaking conservation of angular momentum does not exist in the golf swing as it is not a closed system and we are adding energy to it. However, that doesn't mean that changes in distribution of mass doesn't affect the rotational speed as described in the conservation of angular momentum formula.
Thanks Mike O for the clarity . Im no scientist but i believe this is important part of the deal
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