
New Millennium Golf Science

You're asking: how can pingman (or a pure swinger) release the club if there
is no wrist torque or "centrifugal force"?
We start with the lexicon... a definition of terms:
· position: location in space at a given
instant in time
· velocity: time rate of change of
position... has both direction and magnitude
· acceleration: time rate of change of
velocity... has both direction and magnitude
· kinematics: the study of motion
without considering forces and torques
· dynamics: the study of rigid bodies in
motion including forces and torques
· statics: the study of rigid bodies at
rest including forces and torques
To begin to understand the golf stroke and how club release is affected, one
must have a basic understanding of these simple physics principles. If you
don't then begin here: http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/index.html
I have stated that the only forces (not withstanding the
small contribution due to gravity) that the club experiences are those which
are imparted by the golfer at the grip. He/she can apply a linear (swinger)
force or a torque (push/pull exerted between the two hands... ie hitter) or
some combination of the two. Most likely everyone is some combination of the
two.. but lets simplify and
assume he/she is a "pure swinger" (like pingman) and does not apply
wrist torque.
We calculate the acceleration of the hands from the change in velocity. This
can be done analytically or graphically using vectors as shown in figure 1.
Now that we know the magnitude and direction of the acceleration of the
hands as shown in figure 2
We can use what's known as d'Alembert's principle to solve the
dynamics problem as if it were a simple statics problem.
d'Alembert's principle says: the resultant motion
of a rigid body is completely defined by the resultant and moment resultant
about the mass center of the external forces acting on it.
Remember, in the real world there is only one external force acting on the
club and that is what's caused by the hands moving along their path at an
everincreasing velocity.
Now its a simple statics problem to solve for the
(linear) accelerations ma_{x} and ma_{y} as well as the angular
acceleration alpha. Angular acceleration IS the release!
What have we learned? Lets review...
· The only force necessary to cause the
club to release is imparted to the club by the golfer's hands
· The kinematics of the golfer's hands
are key to knowing when and where the club will release.
· There is absolutely no need to resort
to patently wrong magical mystical totally nonsensical centrifugal force
theories to explain how and why a club releases. Classical mechanics and a firm
grasp of technical concepts are all that are needed.
What I've shown you is how the instantaneous angular acceleration of the
clubhead can be calculated for a brief snapshot in time given only the hand
velocity profile and trajectory. But we're after clubhead speed at impact not
clubhead acceleration at a single instant.
The next step is for you to set the problem up to timemarch the solution
forward then optimize. How and what to optimize are left as an
exercise for the reader. When you've done that, add the effect of gravity and a
wrist torque profile. You'll get out of it what you put into it.
Here's a hint... the only tool you'll need is something like Microsoft Excel.