PHYSICAL
SCIENCE-- 4Ts -- Technique

Canonical
Movements
Basic
human movements mostly of whole body or torso: Turning
head, rolling over onto stomach, curling into fetal
position, stretching, facing, sitting, kneeling, standing,
walking, swinging arms, running, bending down.

Habitual
Movements
Repeated
human movements in daily life, mostly limbs and hands:
Folding arms, shaking hands, opening doors, climbing
steps, eating with utensils, drinking from bottle
or glass, throwing, pitching, tossing, punching, grasping,
reaching, plucking, placing, turning knobs, flipping
switches, pill rolling, tieing laces, fastening buttons
and belts, putting on and removing glasses, pulling
on shirts, sweaters, coats, and pants, putting hands
in pockets, rubbing thighs, rubbing back of neck,
resting head on hand, interlacing fingers, making
a fist, twisting a handle, swinging a hammer, swinging
a stick or bat or club or racket, swimming, riding
a bicycle, driving a car, roller skating, skate boarding,
skiing, surfing, pointing, shrugging, crossing legs,
kicking, stamping, lifting box, shoving box, pulling
wagon, catching ball, watching flying birds and other
moving objects,

Gravity
Trains
all living things about the basic categories of space:
up, down, left, right, front, back, straight up, straight
ahead. Trains all things about movement: walking is
"falling forward almost" over and over again.
Trains all sentient creatures about momentum, mass,
weight, and forces of motion: bowling a heavy ball
versus bowling a basketball. Ignorance of gravity
is ignorance of life on earth.

Biomechanical
Problems

Hand-Wrist
Manipulations

Elbow
Positioning


Impact
Physics - Transfer of Momentum / Sweetspot

-
CBC
MP3 file: The physics of putting Canadian Journal
of Physics, February 2002, vol. 80, no. 2,
pp. 83-96(14) Penner A.R.
-
A.R.
Penner's Physics of Putting (477K .pdf file) -
only click this reference once to load onto your
harddrive
-
Oxford
Croquet - Striking a Ball - Energy and Momementum
Conservation
-
Oxford
Croquet - When A Mallet Strikes A Ball
-
D.
Gugan - Inelastic collision and the Hertz Theory
of Impact, AJP, vol 68 no. 10, Oct 2000: 920-924
-
C.R.
Calladine and Jaques Heyman - The Mechanics of
the Game of Croquet, Engineering, 29 June 1962,
pp 861-863.
-
Ian
Henry's Physics of Golf
-
About
Physics
-
The
physics of baseball
-
Sport!
Science@The Exploratorium
-
Ken
Young's 1998 Physics 208A course syllabus - Physics
of Sports - University of Washington
-
Moment
of Inertia
- Enhancing
the control of force in putting by video game training
Ê Ergonomics,Ê 10 October 2001, vol. 44, no. 12,
Ê pp. 1025-1037(13) Ê Fery Y-A.; Ponserre S.

- Impact
Physics - Face Angle Orientation
-

Impact
Physics - Putter Sweetspot Path
The
trajectory of the putter sweetspot thru space needs
to be a straight-line motion or at least a curve of
even radiusing oriented vertically to the plane of
the surface, at least in the near proximity to impact
and contact with the ball.

Impact
Physics - Path in Relation to Ball Sweetspot
The
straight-line or vertical movement of the putter sweetspot
needs to match the line thru the ball defined by the
points on the opposite sides of the ball's equator
that are closest to the target and farthest from the
target. This ball line includes the ball's center
of gravity in the center of the sphere for a well-balanced
ball. More properly, the movement of the putter sweetspot
needs to transit only thu the vertical plane in the
ball defined by this line and a plane arising vertically
from the surface that includes this line, and the
actual path of the sweestpot needs optimally to transit
thru the center of the ball, whether moving level
or downward or upward in this plane.

Ball-Turf
Physics - Friction

Ball-Turf
Physics - Gravity

Ball-Turf
Physics - Skid, Roll, Decay

Ball-Turf
Physics - "True Roll"

Ball-Turf
Physics - "Ball Balance"


Ball-Turf
Physics - Surface Irregularities & Grain

Ball-Cup
Physics and Optimal Speed at Hole

For
truly consistent and excellent putting, distance control
is key. Distance control comes from touch, tempo and
targeting, as these together automatically create
the right stroke length and hence putterhead speed
and force. With a consistent tempo and calibrated
touch for the green conditions, distance control is
simply targeting and nothing else. With this sort
of command of putting distance, the end speed of the
ball's roll as it nears and then enters the hole is
always exactly the same! The question is what
should this terminal speed of the ball be for optimal
results.

All putts should arrive at the hole with the SAME
drop speed regardless of the green's Stimpmeter speed
and regardless of the length of the putt.
The
range of speeds under consideration extends from too
little to too much. Too little is any speed that doesn't
make it over the edge of the lip, and that would be
zero (0) revolutions per second at the lip. Too much
is the speed at the front lip that does not give the
ball enough time to drop down by gravity as it crosses
the hole far enough so that when it hits the back
wall of the cup it doesn't pop out and keep going.
This speed limit is set by the laws of physics because
the distance a ball drops from gravity in freefall
is always the same and the distance a golf ball must
drop after it crosses the front lip before reaching
the back of the cup is -- at least one-half a ball.
It takes under 2/10ths of a second for a golf ball
to drop half its diameter. Try it: place a golf ball
on your palm, lift it one-half diameter high, drop
it and watch. Pretty quick. Always exactly the same.
If the ball is rolling too fast across the green when
it reaches the lip, it will get to the back edge of
the cup too soon, before the ball drops half way.
Even running straight across the hole so that this
is the longest possible path over the hole, there
is a maximum speed that is too fast. How fast is too
fast at the front lip? 51 inches per second or about
10 revolutions per second. Anything faster and the
ball has NO CHANCE of dropping. and this maximum is
even slower if the putt is not centercut: a path off
to the side of centercut is not as long, and the ball
has even less chance to get dropped low enough. For
example, if the ball enters on a line one inch left
of center, it can't be going faster than about 30
inches per second or 6 revolutions per second. So
the range of speeds under consideration runs from
o to 10 revolutions per second.
How
do you pick a number between 0 and 10? There are three
main considerations.
First,
hardly any putts will be centercut, so you can't safely
use 10. If you want to have at least two-thirds of
the cup available for your ball's path, you have to
slow down to well under 6, so the real range is 0
to 6.
Second, the ball needs enough speed and therefore
momentum to avoid being knocked off line. The only
speed that matters here is the final speed. To understand
what is happening to the ball at this time requires
a quick lesson in putt phases. Every putt has three
phases: skid, roll, and decay. At the start, the ball
is sliding across the green faster than it is rolling,
and the rolling speed is catching up - but the ball
skids until the roll speed matches the slide speed.
This is usually about 15% of any putt's length, depending
on the green's friction and the nature of your stroke.
During the roll, the ball effectively is moving across
the green too quickly to spend much time weighing
down the springy grass blades, so it rolls blithely
along the tops of the grass blades and tips with the
least friction slowing it down. Eventually, however,
the ball does get a little slower and then it sinks
a bit back into the grass blades as it crosses over
them. When this happens, there is a lot more friction
tending to slow the ball - just like applying the
brakes in a car. The ball then slows dramatically
and stops. The onset of this decay phase does not
depend on the length of the putt or the starting speed
of the ball; instead, it always takes place when the
ball reaches a certain slowness for that particular
green. In other words, the decay phase is usually
about the same for every putt for a given green condition.
The shaggier the green, the quicker and more sudden
the stop. Generally speaking, on a medium-fast average
green, the decay phase takes about 1 second and lasts
about 1 foot. On faster surfaces, it stretches out
longer but is also not too different from the roll
phase. During the decay phase, the ball is down and
dirty with surface imperfections like spike marks,
worm droppings, and ball pitch marks. It is also traveling
without much force or momentum, so it is vulnerable
to getting knocked off line. The point of all this
is that it is generally a good idea to get your putts
all the way to the front lip before the decay phase
sets in. That means a miss needs to run at least 1
foot past the cup. For that to happen, the ball's
speed at the front lip needs to be more than 0 and
probably 2 or 3 revolutions per second. So the real
range is between 2 and 6.
The
third and final consideration follows from the fact
that hardly any putts are truly without any break.
Almost all putts have some break. This means that
the vast majority of putted balls enter the cup from
the high side and fall towards a back lip that is
lower than the front lip. This also means that misses
are running past the hole down hill. With a lower
back lip, the cross speed has to be slower still of
the ball will pop out. Also, going down hill makes
for longer comeback putts. Because of these two factors,
it is prudent to slow down the terminal entry speed
even more. So the optimal range is between 2 and 4
revolutions per second.
Since
the decay phase usually lasts about 1 second, a ball
rolling 2 revolutions per second that misses will
run about 10-12 inches past the hole, and a ball rolling
4 revolutions per second will stop about 2 feet past
the hole. Either of these speeds is sufficient to
overcome most surface irregularities, allow enough
time for the ball to drop before reaching the back
lip, allow for lower back lips, and avoid long comeback
putts.
On
the other hand, putting to a cup that lies in a slope
uphill, so the ball is slowing while also running
uphill, calls for more speed. You have a higher backstop
for the back lip and the decay phase is quickened
by the uphill, so the ball will really come to a quick
stop without much worries about the comeback. In order
to take care of surface irregularities, then, the
ball needs some extra juice in this situation - but
only in this situation.
Updated Monday, July 7, 2008 6:14 AM
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