[Mike O]

Mike O

I don't have a precise knowledge of physics, so my use of the term 'angular acceleration' may be incorrect. However, if you look at the hand arc and clubhead arc in the Bobby Jones photo, and look to see how much the hands move per unit time relative to the clubhead movement per unit time, the clubhead is moving a greater distance than the hands - and the clubhead movement per unit time is increasing progressively as the downswing evolves (even though hand speed remains relatively constant). Therefore, I perceive that the clubhead is developing angular acceleration and that this represents the release phenomenon.

Jeff.

Jeff,
Sorry for the bluntness in advance but you're four pages into your own thread dealing with angular acceleration among other things in search of the "truth" and you state "I don't have a precise knowledge of physics, so my use of the term 'angular acceleration' may be incorrect." That's problem number one! Iin finding the "truth" you need to precisely define what you are talking about. With the internet- it's not that difficult to look up the definition. Here is Wikipedia's definition- "Angular acceleration is the rate of change of angular velocity over time. In SI units, it is measured in radians per second squared (rad/s2), and is usually denoted by the Greek letter alpha."

While the clubhead in the Bobby Jones photo is acquiring Angular acceleration (you can measure the radians or degrees between the end of each shaft near the clubhead and see that from one to another the distance is increasing)- however that's only part of the release factors. As it's the linear speed of the clubhead that is the real intent of the release and the clubhead can be picking up clubhead linear speed with an extension of the swing radius and at the same time have no increase in the angular acceleration of the clubhead.

Here is the definition of angular velocity from Wikipedia: "In physics, the angular velocity is a vector quantity (more precisely, a pseudovector) which specifies the angular speed, and axis about which an object is rotating. The SI unit of angular velocity is radians per second, although it may be measured in other units such as degrees per second, degrees per hour, etc."

As you indirectly stated by comparing the differences between the hands and the clubhead movements- it's important to identify which part of the club that you are talking about and what type of speed/velocity/acceleration that you are talking about when having these discussions. For example in regards to the Bobby Jones photo the end of the clubshaft and the clubhead are picking up angular acceleration but the grip end of the shaft is not picking up angular acceleration. However, it's the clubhead speed not the angular velocity or angular acceleration of the clubhead that I think is the essential issue and those are not directly related.

The way you've answered the post above in the quote- it appears that you're implying that the relationship of the hand motion versus the clubhead motion has something to do with the angular acceleration formula of the clubhead - which is doesn't in the strictest sense.

You say "and the clubhead movement per unit time is increasing progressively as the downswing evolves" - here again you can't tell if you are talking angular velocity of the clubhead or the linear speed of the clubhead or angular acceleration of the clubhead? Three completely different things- 1) for angular velocity ignoring COAM- extending the radius has no effect on it - as opposed to 2) the clubhead linear speed which is greatly influenced by an extension of the radius. For example you could have a situation where you have angular deceleration yet with an extension of the radius an increase in the linear speed of the clubhead.