Secrets!

[Patrick Johnson]

Neil:
Explain just how you plan on figuring it all out to see how it actually works without using math.

This isn't a math problem - basic visualization skills are all that are necessary to understand the direction of forces in this ball/ball interaction. For instance, I can easily visualize the sidespin rubbing friction that produces both transferred OB sidespin and throw, and can see that nothing about it can contribute significantly (if at all) to the OB's forward momentum. For another related example, I can also visualize how a spinning cutting blade, by contrast, can contribute to the forward momentum if the material being cut, and why.

Math might be needed to calculate the magnitude of these forces, but their direction is plain for those who can see it.

All you have to do is see what happens, know what you did, and then apply it to similar situations to have another tool in your bag.

Again, if you don't know how what you did produces the results you see, then you have a limited tool in your bag. If you do know how it happens, then you have a less limited tool.

If you don't understand that, then I guess you miss out on the additional tool.

I don't think it's me that's misunderstanding here.

pj
chgo

 

[Mikjary]

Sorry Mike, but I don't think that is a valid test. The reason is because when you applied the right english, you admitted that you had to hit the one fuller. Hitting the one fuller will naturally transfer more energy to the one and leave less for the cb to travel after the hit.

It may not feel like it, but I am pretty sure you actually hit the cb softer on the the spin shot to hold the one from falling in the pocket.

I don't feel this invalidates the premise of the test, just that testing this way doesn't work. Due to squirt, squerve, throw, fuller hit, it would take someone with a heavy math background to figure out how to allow for all the changes or variables involved to actually figure it out. Bottom line is, it works and is another arrow in the old quiver. Who really cares just WHY it works?? All you need to know is the principle behind it working, not all the math behind it. Once you know the principle, then you can adapt it to other shots.

Neil,

No, I said the opposite. :grin: I said the difference in contact points is minimal due to the thicker cut.

Best,
Mike

 

[duckie]

I draw alot from my past experiences and careers in order to understand and make poll my own.

In the past, I raced motorcycles and did some road course driving schools, plus being drag racing in high school.

The common factor in those sports is traction and spinning wheels are not always a god thing such as a top fuel dragster smoking the wheels at the start.

If a wheel speed exceeds the available traction it will spin with very little affect on forward motion. But match the speed of the wheel to a level that doesn't exceed the available traction, you get maximum transfer of power.

Seem thing applies to a spinning CB hitting a OB. Too much speed on the spin and it exceed the traction between the CB and OB, so there us little affect.

Hit the OB to fast with the CB, there is not enough time for the transfer to happen.

Also the angle of the spin on the CB comes into play.

Everything has to be just right for the CB spin to add to the OB speed. This concept cannot be applied to all shots.

There is a small range of cuts shot and ball placement on the table that adding speed to the OB will work on.

 

[Mikjary]

I draw alot from my past experiences and careers in order to understand and make poll my own.

In the past, I raced motorcycles and did some road course driving schools, plus being drag racing in high school.

The common factor in those sports is traction and spinning wheels are not always a god thing such as a top fuel dragster smoking the wheels at the start.

If a wheel speed exceeds the available traction it will spin with very little affect on forward motion. But match the speed of the wheel to a level that doesn't exceed the available traction, you get maximum transfer of power.

Seem thing applies to a spinning CB hitting a OB. Too much speed on the spin and it exceed the traction between the CB and OB, so there us little affect.

Hit the OB to fast with the CB, there is not enough time for the transfer to happen.

Also the angle of the spin on the CB comes into play.

Everything has to be just right for the CB spin to add to the OB speed. This concept cannot be applied to all shots.

There is a small range of cuts shot and ball placement on the table that adding speed to the OB will work on.

This is true, and I have been trying to isolate these shots. Speed and stroke are major factors in my search. This seems to be doomed to people's impressions rather than actually trying the examples I've posted for themselves.

Best,
Mike

 

[ShootingArts]

centers

PJ,

In a straight on hit the travel path, center of gravity of the balls, the pivot points on the cloth for the balls, all of these things are on a single line. In this unique set of circumstances there is nothing to work against so you get no effect on ball speed. However once you move these things out of line on a cut shot you now have something to work with and against. Anchor points don't have to be fixed only resistant to movement. Impossible for spin not to add or subtract speed depending on where it is applied except as noted in the one unique situation of all centers being on the same line.

The spin being at a right angle is a red herring in this case. Impossible for the forward speed and spin not to both appy force to the object ball and when they do then the direction of force will be neither the exact direction of cue ball travel or the "right angle" of the spin. That isn't really a term I like because an arc can't be at a right angle to anything and the contact between balls is an area not a point. Regardless, both forces have to modify each other, no other option. That leaves us discussing the degree of effect and that we can discuss for days, I'm far too lazy to start investigating slip factors and all of the things that go into modeling a collision. Much easier to do as Mike has done and go hit some balls.

No shop to play in for a few years or I would at least build a fixture to give a repeatable impact to a cue ball, much like Joey's pinball machine. As it sits right now we are working with too many variables to isolate one and concretely prove what it does or doesn't do to everyone's satisfaction.

Hu

Of course - the question is whether any of it goes into increasing OB speed.


The drawing doesn't depict only a straight shot - it's the same no matter what the cut angle.



The optimum attack angle for sidespin to have maximum effect on the OB is straight on. But I think you're talking about the "leading and trailing edges" effect of your cutting tool analogy - see my comment about that below.


OK, but if the cutting tool's spinning edges are adding or subtracting from the travel speed of the material being cut, then it's because the spinning edges are spinning at least partly in the direction (or against the direction) of travel speed. This isn't true of a CB with sidespin - its spinning direction is always at a right angle to the OB's travel direction - don't forget that as the cut angle changes, so does the OB's travel direction, keeping it always at a right angle to direction of CB spin. There is no "leading or trailing edge effect" with CB/OB contact.


And with slower sidespin (half or less of maximum sidespin), with the counterintuitive result that inside spin often results in less throw (and less transferred spin) than no sidespin at all, and outside spin can result in more throw and transferred spin, in the opposite direction of the spin.

pj
chgo

 

[lfigueroa]

Someone told me that Dave Matlock had run 20 racks or so of 9-ball in KCMO. In discussing this, the person said "Matlock has a system for everything." If this is true, do you know what that tells me about Matlock? That tells me that he has shared "secrets." Otherwise, we wouldn't know about how he just made that incredible shot. We would just assume great talent. But we should anyway, because it took talent to come up with any system that works, and his apparently do. I have met him and he seems like a friendly guy, so it does not surprise me if he shares secrets.
I define a system as a general idea of how to play a particular billiard shot, which can be or ought to be adjusted to fit conditions such as humidity and situations such as layout. I told a well-known billiard author about one of my systems that I came up with for kicking in one-pocket 3 rails when you are against or close to the first rail. He ANGRILY said "know what I think of your system? I think your system sucks!" Well, he is a former national champion who I was friends with for years, and he did not share any systems from his chosen game. My system uses extreme english, and he has an extreme english system, so I think he thought I was plagiarizing or something. But my system works on 7, 8, 9, and 10-foot tables and is easy to adjust. It works for all my friends who have tried it. If that "sucks," then I wanna learn everything that sucks. If you read Plato's story, you will understand part of the reason that not all players share secrets. It is not always out of selfishness. Sometimes it is out of wisdom. And sometimes it is because the man with the secrets has nothing left in life but those secrets. Plato would tell you that sharing knowledge can also get you attacked by those who want to stay in the darkness.

Doesn't mean he has shared secrets -- just means he has let on that he has systems for about everything.

I have played guys like this and it is brutal -- guys who seem to have a system for certain banks will drive you absolutely nuts because *they know* they are either going to make the ball, hang it up, or leave it within inches of the hole (1pocket), as opposed to guys who are just flinging the ball towards their hole. It will drive you to drinking.

Dave strikes me as a pretty methodical guy, so he probably has "fractionated" many, many shots down to an internal system, or guide, or rules of thumb, that he knows he can rely on. It makes him a killer and basically, thats what all players should aspire to, no?

Lou Figueroa

 

["CaliRed".]

for those of you wanting to use the WEI table, I made a video a couple of years ago. For the most part, everything still applies in it. A few people mentioned the volume might be a tad low, so you might have to crank it up a bit.

There's 2 parts to it. This was made for my buddies over at onepocket.org, so the first 2:45 seconds of it was telling them how to navigate around a bit.

Just remember a few things that have changed. You must register over at http://pool.bz first before you can create a table. Once your registered, go here to create a table http://pool.bz/CueTable.php .

After creating the table and clicking the Copy Layout URL, come over here, start your post and when you're ready to insert the table, click the blue WEI icon up there in the tool bar in your post. Don't cut or copy anything else in between the time you hit Copy Layout URL and the time you paste it in your post, or you'll wipe out what you copied into memory. Tip: Open the wei site over in one tab, open azb up in another.

This was a basic WEI tutorial and does not go into advanced stuff.:smile:

Hope that helps someone out there. Take a hour of your time and learn to play with it.. it goes a long way to illustrating shots for all of us to discuss. If anyone has questions... please start a new thread and we can discuss them there. I don't want to derail this thread, so just start a new one please. Thank You.

 

[The Renfro]

Basically I think it comes down to rotational energy transfer. On thicker hits there is enough transfer to cause english induced throw... On thinner hits where there is not enough transfer to cause throw there may be enough transfer to add a small bit of speed.

My thoughts go back to at what angle can you no longer throw a ball with english? That would be the point that I would look for a speed increase instead of throw....

By the time you reach 90 degrees there may not be enough rotational energy transfer to add anything unless you use an apparatus that can exceed the RPMs that can be accomplished thru a conventional stroke thereby increasing the potential rotational energy......

I would also think that the speed increase would be roughly the same regardless of rotational direction when it occurs. The inertia of the object ball at rest will allow rotational energy to transfer... But will not allow enough to transfer to alter the OB path... Either direction of rotation up until this angle will be able to english throw and alter the path...

Conceptually I think the added speed has to exist in a certain window... I think the window opens when throw ceases to occur but I have no clue when the window will close shut....

 

[Mikjary]

I think this window is best demonstrated with cuts that are greater than 45 degrees and increases with cut severity. I looked at the spin shot I previously showed where I cut the ball about 90 degrees. I entertained the idea briefly that because of swerve the possibility existed that the cue ball was contacting a larger portion of the object ball than a straight cut did.

The amount of object ball I hit when I spun the cue ball is so small, it doesn't justify even considering it to be a factor. The cue ball travelled a half table less yet the object ball travelled just as far on both shots (See post #363).

If these shots are tried, rather than speculated, the user will discover my point. And that is, when there is a thinner cut and the momentum of the ball collision/impulse is not a larger factor in the object ball speed, extreme spin can ADD to the speed of the ball. ADD, not be the sole provider of roll. The object ball can gain a small amount of speed from spin. On straighter shots, the force of the collision is greater than force of the spin.

Best,
Mike

 

[JB Cases]

Doesn't mean he has shared secrets -- just means he has let on that he has systems for about everything.

I have played guys like this and it is brutal -- guys who seem to have a system for certain banks will drive you absolutely nuts because *they know* they are either going to make the ball, hang it up, or leave it within inches of the hole (1pocket), as opposed to guys who are just flinging the ball towards their hole. It will drive you to drinking.

Dave strikes me as a pretty methodical guy, so he probably has "fractionated" many, many shots down to an internal system, or guide, or rules of thumb, that he knows he can rely on. It makes him a killer and basically, thats what all players should aspire to, no?

Lou Figueroa

Dave has systems for everything. He also does not LOOK LIKE he is using any systems when he plays. I drove cross country with Dave once and he talked about some of the systems and why he uses them.

One time we hired Dave to do a weekend's worth of exhibitions. My wife told Dave to try to run out every rack of eight ball in order to make the games go quicker. My regret is that I didn't have a video camera set up over the table or I would be making money FOREVER simply by selling that video. Dave simply made shots through the weekend that were unbelievable and seemingly physics-defying. Some of the most impressive pool I have ever seen and a real treat for all of us who got to watch it.

 

[ShootingArts]

just a reminder

I think this window is best demonstrated with cuts that are greater than 45 degrees and increases with cut severity. I looked at the spin shot I previously showed where I cut the ball about 90 degrees. I entertained the idea briefly that because of swerve the possibility existed that the cue ball was contacting a larger portion of the object ball than a straight cut did.

The amount of object ball I hit when I spun the cue ball is so small, it doesn't justify even considering it to be a factor. The cue ball travelled a half table less yet the object ball travelled just as far on both shots (See post #363).

If these shots are tried, rather than speculated, the user will discover my point. And that is, when there is a thinner cut and the momentum of the ball collision/impulse is not a larger factor in the object ball speed, extreme spin can ADD to the speed of the ball. ADD, not be the sole provider of roll. The object ball can gain a small amount of speed from spin. On straighter shots, the force of the collision is greater than force of the spin.

Best,
Mike

Mike,

I worked in R&D years ago. One thing I can tell you, empirical testing trumped theory every time. I had some hand in working on the theory and I often set up the tests. When the test was set up in a valid manner and worked, math to the contrary was never right. When the test didn't work, all the proofs on paper in the world didn't help.

Right now you know that by adding spin you can transfer greater force to the object ball while still sending it on the same path. You know that as long as you execute the shot correctly the results are consistent. A bit more testing will establish the boundaries of angles and speeds that this procedure functions within and at that point you can happily transfer your knowledge to other shots when they come up.

Ultimately when you know cause and end effect it isn't necessary to know exactly how that end effect is created. This subthread is interesting but ultimately serves no purpose on a pool table.

Does the spin let you cut the ball fuller and keep it on the same path?

Can spin add speed to the object ball by transferring some of the force of the spin?

Does the ball go in the hole with spin when it won't without spin? Easy to see that this is the only question you must have the answer to in order to pocket the ball or try another shot.

An interesting fixture would be one that forced the cue ball to hit the object ball in the exact same place, with and without spin. Obviously the object ball would take different paths but which way would it roll longer?

Hu

 

[Mikjary]

Hu,

Great minds think alike. Earlier, I was thinking about just hitting the object ball thin to a rail and see how much distance I got out of the cue ball. I could hit the same contact point and control the distance the object ball travels, with and without spin.

The key is the amount of cut. It should be 80 or more degrees to factor out collision/impulse between the balls. What say you?

As an aside, I've been talking to some pro friends who've validated the increase in speed and are curious about its cause.


Best,
Mike

 

[Cuebuddy]

Mike,

I worked in R&D years ago. One thing I can tell you, empirical testing trumped theory every time. I had some hand in working on the theory and I often set up the tests. When the test was set up in a valid manner and worked, math to the contrary was never right. When the test didn't work, all the proofs on paper in the world didn't help.


Hu

This paragraph reminds me of bit of knowledge my father passed on to me years ago.

"If the map and the ground disagree> the map is wrong"

 

[Jal]

Here is a definitive simple shot that illustrates the principle that side spin increases object ball speed/travel. .....

Is it your contention, or maybe 'tentative hypothesis' might be a better description, that a ball rolling on the cloth with a sidespin component will travel farther than one without the sidespin component?

Jim

 

[Mikjary]

Is it your contention, or maybe 'tentative hypothesis' might be a better description, that a ball rolling on the cloth with a sidespin component will travel farther than one without the sidespin component?

Jim

Hey Jim,

No, I wasn't really trying to get into that. I agreed with PJ's analogy about a barrell rolling on its edge. My contention :smile: is that an object ball will pick up a small amount of speed from the extreme side spin of the cue ball on a thin cut.

This small transfer of speed is possibly proportional to the decreasing amount of force from the impulse of the cue ball and object ball. I seem to see it most when I cut balls 80+ degrees.

I am about to post another cue table diagram that Hu inspired. Joey A. gave permission to me to be as much of a PITA as I wanted to be in his thread and I will probably take him up on it. I feel this point about spin/speed transfer is an important one. The answers ultimately lie in either high speed video or answers from posters such as yourself with the math/physics expertise.

Best,
Mike

 

[Patrick Johnson]

In a straight on hit the travel path, center of gravity of the balls, the pivot points on the cloth for the balls, all of these things are on a single line. In this unique set of circumstances there is nothing to work against so you get no effect on ball speed. However once you move these things out of line on a cut shot you now have something to work with and against. Anchor points don't have to be fixed only resistant to movement. Impossible for spin not to add or subtract speed depending on where it is applied except as noted in the one unique situation of all centers being on the same line.

The spin being at a right angle is a red herring in this case. Impossible for the forward speed and spin not to both appy force to the object ball and when they do then the direction of force will be neither the exact direction of cue ball travel or the "right angle" of the spin.

So you're saying a cut shot changes the way the CB's forces affect the OB compared with a straight-on shot. I don't think so - here's why:

If you freeze two OBs together so that the combo is pointed straight at the center of a pocket, and then shoot the CB into the first OB at an angle, the second OB will not go to the center of the pocket but will be thrown offline. You and I are very familiar with this phenomenon.

But if you wet the two balls at their contact spot before freezing them together, eliminating the friction between them, then the second OB will not be thrown offline but will go directly to the center of the pocket.

This shows that, with a cut shot, the force from the cue ball's travel isn't applied to the OB in the direction of the cue ball's travel but along the line between the balls' centers, indicating that a collision at an angle acts just like a straight-on collision. And, just like in a straight-on collision, the force of the cue ball's travel and the force of its spin are applied to the OB in directions perpendicular to each other. If sidespin adds speed to the OB in one case, it must add speed in both cases.

pj
chgo

 

[Mikjary]

This first shot is with a center ball hit, no english and cutting the one ball as thin as I could cut it over to the rail. After many attempts, with the thinnest cut being close to 90 degrees, the cue ball landed very close to the resting point I show on the diagram.

CueTable Help

With the same setup on the second shot, I used extreme right center spin and lagged the one ball over to the rail again. I hit the same contact point and the one ball travelled the same distance as on the previous shot. Notice the difference of cue ball travel on the second shot.

CueTable Help

Best,
Mike

 

[Patrick Johnson]

This first shot is with a center ball hit, no english and cutting the one ball as thin as I could cut it over to the rail. After many attempts, with the thinnest cut being close to 90 degrees, the cue ball landed very close to the resting point I show on the diagram.

...

With the same setup on the second shot, I used extreme right center spin and lagged the one ball over to the rail again. I hit the same contact point and the one ball travelled the same distance as on the previous shot. Notice the difference of cue ball travel on the second shot.

If you hit the same contact point, why does the CB carom off the OB at such different angles?

pj
chgo

 

[Mikjary]

If you hit the same contact point, why does the CB carom off the OB at such different angles?

pj
chgo

Swerve adds to the cue ball direction. The difference in contact points is so small, it was insignificant. I contacted the extreme edge of the object ball on both shots.

The example is a simple experiment. The large difference in cue ball travel between the shots can't be ignored.

Best,
Mike

 

[conetip]

With the same setup on the second shot, I used extreme right center spin and lagged the one ball over to the rail again. I hit the same contact point and the one ball travelled the same distance as on the previous shot. Notice the difference of cue ball travel on the second shot.

Best,
Mike[/QUOTE]

So, If you hit with alot of Right spin, why does the cueball come off the cushion to the left, instead of back to the line it came from or cuts further to the right?
Did the object ball have any change in it's direction with the same thin cut as was previously with the centre ball hit?
Thanks, Neil