Impact Physics

Essential Reading
1

Homer is correct in that separation speed is not only effected by club head speed prior to impact but also speed after impact. It is not hard to understand that the greater the clubhead speed after impact the more energy is being transfered into the ball… sustaining lag pressure and holding the line of compression, and maintaining a pre stressed shaft through the impact area. Whether or not high speed cameras, radar or other means of scientific monitoring applications prove or disprove what is actually happening with regard to torque, shaft flex, material density compression, and on and on… educated hands with the help of the computer will make the necessary fine tuning adjustments for you. The bottom line is that your INTENT is to maximize acceleration through the hitting area. For this to happen, you must feel, or perceive that maximum hand speed is happening well past impact. Your ability to actually approach this “Holy Grail” will have to do with many things, and there are all kinds of drills and exercises you can do to move things in this direction.

Acceleration translates into lag pressure which translates into feel, which for me translates into my ability to feel the club head in my hands though the 1 – 2 and 3 pressure points. If I can feel the club the ball is my oyster, and I can draw, fade, adjust trajectory and allow for the magic to flow from my educated hands into golf shots that do exactly what I have envisioned in my minds eye, hitting the green, spinning the right way towards the flag and maybe even dropping into the cup from anywhere within my range of distance possibilities. It’s the most wonderful thing when all the science that we study becomes nothing more than a look, intent, a motion, and a result that is the product of our fine tuned intuition.

Anyone saying that ball speed is only a result of pre impact clubhead speed does not fully understand the properties of inertia, acceleration, compression and so forth. Just smile and continue your pursuits.

2

I believe that high science has shown that ball speed is affected by clubhead speed measured at two moments in time, pre and post impact. This is not a mystery…just common sense.

If you were playing Rugby and you are the one standing still, and someone comes running to tackle you, would you rather he hit you and you don’t move as he drops to the ground? … or would you rather he hit you and suddenly you go flying right along with him? Can you feel that? That is what the golf ball feels… the greater the speed after impact the harder the hit… common sense…

If we know this to be true and I think we all do… then what are the power accumulators left after impact to keep the clubhead driving through the ball? There must be something going on after impact…
If your right arm has straightened on the way down and it is spent,
the wrists have uncocked and rotated, we only have #4 if we have not spun out too early, or as Ben Doyle used to say to me “hips running down the fairway”. If we continue to try to accelerate the club after impact to the 4rth parallel with #4 and now even beyond,
(remember acceleration means speed is increasing exponentially)
we would need to continue our efforts to move the club as quickly as possible long after the ball is gone.

I can say this, if I were to finish my swing on an elbow plane, (extremely flat) I can guarantee I would lose lots of distance.
Has anyone ever seen a thunderous ball striker finish with their hands belt high and around their body and behind them? I would imagine not… if so, please let me see this really.

Long hitters will pass their hands through a very high position at some point in their finish…they may retreat to something that looks flat as their hands drop down from a high finish……you see this look from the long hitters and long swingers…

With hitters, they have the best chance to capitalize from the 5th accumulator because of the position of their hands at the 4th parallel. In other words, by using radial acceleration and an angled hinge their hands will be close to the body just inches away, so they have all this room to now rip the clubshaft up to a shoulder plain.
This takes a lot of force, and it is this force that is now taking over for the spent #4 after the hips have cleared out and are spent, the torso has rotated around and their is really not much else the pivot of the body can do. The upper arms have been tightly packed against the body and now it is their turn to release, so they separate from the body with what I think would be the rotator cuff muscles and raise the shaft from elbow to shoulder plane in a very quick and powerful motion.

Now in a swinging procedure, there is no 5th accumulator because after impact the clubhead has been accelerating longitudinally and all the force is to be dumped into the ball and downward into the ground, via the arc of approach, so after impact the upper arms release from the body and the hands move away from the body, they do not stay in close like Hogan, or other classic hitters.

I think a lot of people really don’t understand the difference between radial acceleration and longitudinal acceleration.

The best way I can describe it would be if you are using longitudinal acceleration you are trying to throw the force of the clubhead into the ground below you and somewhat towards the target but out to the right and into the earth below you…. as compared with radial acceleration you would be trying to throw the club at the target or even better yet, left of the target and somewhat skyward.

So if you were to try to find your lost club, if you are a swinger, you would start walking toward the pin, take about 10 steps, then make a 90 degree right turn, take another 10 steps, then get out a shovel and dig a hole in the ground about 30 feet deep to find your club.

If you are a hitter, you take 10 steps toward the pin, then a 90 degree left turn and then take 10 steps, you would then look up into the trees and try to spot your club you just tossed up there about 30 feet up in the tree.

Very different intentions

3

Experiencing the difference between centrifugal and centripetal forces in the golf swing…

The first is acceleration of the club away from the center, and the second is acceleration towards the center.

When you start your downswing, the club should tighten and compress towards your body (centripetal), then as the club continues it’s downward descent towards the ball, the club then moves away from the body, expanding (centrifugal).

centrifugal and centripetal force should not be confused with longitudinal and radial acceleration…

As the clubhead gains speed, centrifugal outward force will make the club feel heavier as it gains inertia…

As a hitter… the slamming of a door feels correct as the angle hinge slams into impact and keeps an open to square feeling from parallel 3 to parallel 4.

A firm and heavy feeling through the impact arena is certainly desirable… as long as this feeling is maintained well beyond impact.
Sustain the lag…

The feeling of too much centripetal force can lead to over acceleration for most people… unless you have a world class left hip, and Popeye’s forearms… slow, slow, slow, then go, go, go……!!!

4

If a body revolves in an ellipsis; it is proposed to find the law of the centripetal force tending to the CENTER of the ellipsis.

– Isaac Newton (1687) PROPOSITION X. PROBLEM V.

Centripetal and Centrifugal Forces

The Latin word “petitus” means inclining towards, and the Latin word “fugo” means to drive away. Hence the European scientists of the 17th century (who customarily composed their scholarly treatise in Latin) used the terms centripetal and centrifugal to refer to effects directed towards or away from (respectively) some central point.

I am quite sure we can accept that as a golf club changes direction at the top of the swing, and the torso starts to accelerate it has a tendency to compress the club and shaft into or towards the body.
(Centripetal)

As the body rotation continues at some point the club is whirled into an outward expansion, the inertia of an orbiting clubhead is said to have a centrifugal effect, because continued motion in a straight line would tend to carry the object away from the center. (Centrifugal)

I am quite sure that if I attach a bowling ball to a chain, and swing it around as fast as possible, and you try to catch it in your gut, these forces won’t by any means feel fictitious!

5

First we must understand that to hit a straight shot, we need the clubface square to the plane line at seperation, not initial impact.
it will appear to be slightly open at initial impact… closes some, and need to be square at separation. This is why if you look at the world’s greatest ball strikers, they have the clubface much more open at 7 o clock than your average golfer. This is the result of effective power accumulator #3 doing it’s job.

Second, the longer you can hold the ball on the clubface the better.
Even for short shots. Even for putting. You can hit a 3 foot putt with a rapidly accelerating clubhead. Try it…

Acceleration is the holy grail of the game. Acceleration is lag pressure.
Lag pressure is Feel. Golf is a game of feel.

Now to clear up the centrifugal debate, it’s the same argument that Einstein makes about gravity itself. Does gravity exist. Einstein says no. He argues that space itself is curved, therefore something that appears to be falling is actually just occupying it’s natural position in curved space. When you jump off a cliff, there is no force acting on you at all (assuming you are in an air vacuum for you quantum purists! lol). It’s only when you hit the ground that a force is exerted upon you.

Let’s leave the centrifugal force topic to the Einsteins of the world,
and we can go with the force being real because whether or not it is real, the club hits the ball with force, and your body breaks into pieces when you jump off a cliff and hit the ground. It’s real enough for us to play golf.

6

I was doing some back tracking of old pages with old threads…and just returned this one to the top of the queue in an effort to remind everyone that there is some great posts way,way back when Lag initially set up the forum and posted his views on numerous subjects to get the ball rolling --so to speak
It’s well worth a look back for those that haven’t ventured into the depths of the forum…
for e.g This Public forum has 11 pages of threads. It may do some a great service to head back to page 11 and re-read some of these nuggets and then work backwards thru the threads … there is some excellent stuff to jolt our memories on many terrific subjects

7

Just finished reading this thread and had the same thought…bump.

8

And another year later, this will get another bump!

Hoganut spent MANY hours trying to find this thread as he thought it was important that
1teebox and I should read (or re-read). Thanks for digging Tom, great info here!!

bent

bob

9

Yep a great topic and thread here, and like Two said the tons of early stuff from Lag to get the ball rolling is simply the best stuff on the planet for those that will open their eyes and mind to the realm of intentions, oppositional forces, and lagpressure. :sunglasses:

10

In regards to centripetal force at the start of
the downswing, do we want to keep that feeling
as long as possible ? Is this the free Ride down?

If so how is this best accomplished?

11

Module 6. :wink:

I’ve been on it for almost a week, and it is eye-opening for sure.

12

What advice would u give to someone in mod 3?

13

One thing puzzling me since stealing cheese and eating it, has been about contact.

My iron strikes are inward from the center of the face- between the center of the face and the heel area…but the persimmons are hit right smack dab in the middle of the screws on the insert.

So why isn’t the persimmon strike more inward on the insert?

Too complicated for small rat brains to determine…anyone have any ideas. Oh yeah, I play the ball basically in the same relative location to my eyes as I see it…like 5L.

14

There is nothing high science about this. It’s a very basic application of Newton’s Second Law and the Conservation of Momentum.

Conservation of momentum:
Momentum is defined as the product of the mass of an object and it’s velocity: p=mv
The conservation of momentum is a fundamental law of nature which states that if no external force acts on a closed system of objects, the momentum of the closed system remains constant.
Therefore, the momentum of two colliding objects will change from the moment they contact to the moment they detached if one of the objects is accelerating (i.e external force applied to the system).

Newton’s Second Law:
F=ma or F=mv/t or F = p/t

Relating Momentum to Newton’s Second Law:
Fnet = (pf -pi)/t = m(vf - vi)/t
where; pf = final momentum, pi = initial momentum, vf = final velocity, vi = initial velocity, m=mass of club, and Fnet = net force applied over a given period of time t.

Therefore, for the period when the golf ball and club head first make contact to the time when they seperate, if the club head is accelerating during this very very small interval of time (i.e vf > vi) then the net force applied to the ball will be greater when compared to the condition where the club head decelerates. This will ultimetly translate in greater ball speed.

So the critical parameters are the club head velocity at the start of impact and at the end of impact, but keep in mind that impact lasts for approximetly only 400 microseconds :wink:

15

Ratter, the weight of a long hosel on an old blade will make the sweetspot nearer the heel away from the centre of the blade. Get youself some decent clubs.

16

in regards to nrg’s comment, on my '53 macgregors most of the weight on the back of the club is just inside
of center towards the heel, which tells me that is where i should hit it. i like clubs that tell you on the back design where
you should hit it. i like drivers with screws, just hit it inside of those.

17

Still cornfused ( a Bom term I think ) here.

I am using the remakes of the Colokroms and some black paint MacGregor persimmons- both for practice. The black paint is mostly for blocks not quite up to speed, so the wood is painted to cover the irregular grain, etc. However, the puzzling question still remains. Why on the Colokrom strikes the strike is inward from the center of the face, but on the persimmons it’s in the middle of the insert. I would think the persimmon, especially my fairway woods, would have the strike mark on the inward portion of the insert given the same dynamics.

Good practice clubs those are. I am saving my Palmer persimmons for playing only- which I haven’t done yet this year, but what a great feel and sound to them.

Just curious why that is. :slight_smile:

18

He could always pull a Johnny Miller and cut off some of the hosel to shorten it and move that sweetspot back to the center. :smiley:

19

True, but when you plug in real world numbers the distance gained between a clubhead that accelerates to 100 mhp and remains constant @ 100 mph through impact and a clubhead that continues to accelerate at the same rate is less than 1 yard. I suspect you know this if I am interpreting your last statement correctly :sunglasses: There are no doubt advantages to having your brain tell your body to continue to accelerate but they work because they ensure you don’t actually stop your rotation prior to impact. Our brain guides our bodies and the delays in message signals and imperfect nature of our assembly means we need to stack the deck in our favor.

20

Well if the above question about strike location was too hard, here is something else. :slight_smile:

The other day I was showing a few people shot shaping, or at least opposite flights/impacts. Started with draws v. fades, then from slices v. hooks, highs v. lows, fat v. thin, toe v. heel hits, shanks v. smothered, etc…showing the opposite relationship to each other. The last one I could think of at the moment was a “topped” shot, so I topped a couple just perfect, but after I did that I drew a blank on what the opposite of a topped shot would be.

Stood there for a spell, and nothing came to mind, which is easy for an aged mind as we mostly have a blank canvas. :laughing:

Does a topped shot have an opposite?