Paging any physicists or engineers...goofy question inside

So, whilst reading on the pros and cons of a 10-finger grip, a question bubbled to the murky surface of my brain goo.

One of the potential cons of it was the possibility of the hands separating, with the trail hand sliding down the grip towards the shaft.

So, if my right hand slides down the shaft, doesn't that move the fulcrum of the lever (the club) towards the head, increasing the power of the grip end lever arm? Also, wouldn't that shorten the head end lever arm, increasing the speed of it's movement? (And decreasing the radius of it's arc.)

Now, remember that, in my world, there are numbers and there are letters, and the mixing of the two is an abomination unto the eyes of God.

So, bear that in mind when you 'splain this to me.

The hockey slap shot - fast and powerful. May be a bit tough to make sufficiently repeatable for the purposes of smacking a tiny white ball a long way.

Ah. science. Cleveland. The scene of my engineering education. Actually, I knew Archimedes ("Give me a lever large enough, and I will move the world.") He, of course, was a Greek.

Your thought process is not that bad. You are thinking of a lever, which is a linear force multiplier, but what is going on here is a rotation of the clubhead around a point - think of swinging a bucket, at the end of a rope, around your head. In the case of a golf swing the path isn't truly a circle, because both the center (the hands) and the clubhead are both in something of a circular motion at the same time. Engineers would break it down into a series of very small movements that would be very close to a series of arcs.

Let's assume that during the swing both the hands and the clubhead rotate in circles with the spine as the center. Again, I'm simplifying a very complex motion because the principles are the same. Let's say the hands and clubhead both travel 180 degrees. Let's say the hands are one foot from the center of rotation, which means the hands travel about 3.14 feet. If the clubhead is on a club that puts it 3.5 feet farther from the center of rotation, the clubhead travels about 14.1 feet IN THE SAME TIME. SO if the hands are moving at 25 mph, the clubhead is moving at 112.5 mph. If the right hand slides down the shaft, two things can happen: 1) the splitting of the hands makes it a little more difficult to rotate the wrists and release the club - let's not consider that because it does not matter to your question, and 2) it has the effect of making the club shorter, sort of like choking up on the club, which reduces the clubhead speed. Shortening the length of that four foot club by three inches, either by choking up or shortening the shaft, would lower clubhead speed from 112.5 to 106.2 mph.

So shortening the club length decreases rather than increases clubhead speed. It's why long drive contestants have insanely long shafts on their drivers.

It is true that figure skaters increase their spin rates by bringing their arms into their bodies, but that is about conservation of angular momentum, not generating maximum speed three feet away from the axis of rotation.

I wrote this quickly. Ask away if you have questions.

Reframmellator said:

So shortening the club length decreases rather than increases clubhead speed. It's why long drive contestants have insanely long shafts on their drivers.

Click to expand...

This ^^^^

JayB said:

The hockey slap shot - fast and powerful. May be a bit tough to make sufficiently repeatable for the purposes of smacking a tiny white ball a long way.

Click to expand...

Interesting point. Baseball players keep their hands together when they bat to facilitate "breaking of the wrists" during the swing to generate still more bat speed. And yet, I remember reading a story about Honus Wagner and Ty Cobb, arguably the two greatest hitters of the dead ball era. They met for the first time in the 1909 World Series, when some enterprising photographer thought it would make a great picture to have the left hand batting Cobb and the right hand batting Wagner in their respective batter's boxes in their batting stances. Before the picture was snapped, the two looked at each other in amazement - both had about a one-hand-size gap between the hands when they gripped the bat. Neither of them had ever come across another batter who used that grip until that day. So the split hand grip is probably pretty accurate in the right hands.

Wouldn't the splitting of the hands add 1 more thing to the kinematic sequence and the slowing of the left hand increase the speed of the right and increase the speed of the club head? Same effect as hips/chest/arm slowing down right before the club reaches its top speed. No clue if that increase would make up for the shortening of the club or not.

See ball. Hit ball. There.

Obviously, I am sooooo not the engineer type. My son is though, future's quite bright. Ahem...

Play on!

ntanygd760 said:

Wouldn't the splitting of the hands add 1 more thing to the kinematic sequence and the slowing of the left hand increase the speed of the right and increase the speed of the club head? Same effect as hips/chest/arm slowing down right before the club reaches its top speed. No clue if that increase would make up for the shortening of the club or not.

Click to expand...

The straight line velocity of the right hand has to increase, but the angular/rotational velocities of the LH/RH/clubhead HAVE to be the same. The farther from the center of rotation, the higher the straight line velocity.

Forget for this discussion the loading and unloading of the shaft. The left hand, right hand, and clubhead are all in a straight line. So they will all travel the same number of degrees (physicists say the angular velocities are equal) in the same time, but the clubhead will move faster than the right hand, which will move faster than the left hand. Angular velocity is the key here in terms of what the hands/shaft/clubhead are doing.

Again with the skating example - we've seen those big, long pinwheel formations where the skaters skate around a center object, usually a skater. Then other skaters join the line one by one. By the time skater number 6 or 7 joins the line, (s)he has to be flying to catch up and join the line, while skater number 1 is barely moving. Skater 3 may lag the line briefly, or skater 5 may get ahead of the line briefly, but that cannot impact the speed of the one at the end without something catastrophic happening to the line.

Hope that makes sense. I'm on the chemical side of engineering, not the mechanical side, and I thank freshman physics for that. I look at these things by trying to visualize what is happening in a real world situation.

I'm glad these questions were asked. In trying to answer them, I've had to eliminate some effects that we know are happening. That has reinforced for me that the simpler my swing, the more repeatable it is likely to be.

WMac19 said:

See ball. Hit ball. There.

Obviously, I am sooooo not the engineer type. My son is though, future's quite bright. Ahem...

Play on!

Click to expand...

Good for him. If you ever need some engineer jokes, look me up.

Fulcrum in the swing is the shoulder. Club/hands are pivot points. As was mentioned earlier the further down the shaft the pivot moves the slower the club moves. While the bottom hand can be used for the speed if it flips or has more control than the top hand then flipping can occur and again moves the pivot point down the shaft and decrease speed

The engineer guy put it about as well as it can be put.

For normal folk, If you take a object spinning at a set rpm that is say 3' in diameter, and another that spins at the same rpm but is 4' in diameter, the tip speed will be substantially faster on the larger diameter item. One of the reasons most club manufacturers started making driver shafts longer. The potential for faster club speeds are much greater with a longer lever (shaft) with the same effort.

That's why when you buy a truck that has say 30" tires on it your speedometer will read quite a bit slower than actual speed when you install them 36" mudders.

Reframmeliator, and everyone else, thank you. I'm now edumacated.

Also, it makes my crusty old heart happy to see the duality of Man in the fact that you are a very smart guy who has an avatar with Larry Storch.

You're certainly welcome. As far as Larry Storch, my parents never attended college, but they were insistent that their kids have a broad exposure to and appreciation of the best culture our civilization has developed.

If you want to learn more there is a book called The Golf Swing: it’s easier than you think, by Chris Riddoch that does a great job explaining the physics behind the motion. The book has an extensive list of reference documents for those who would like to dig deeper.