setting cue ball in motion

hang-the-9 said:
You may put all those things in scientific terms, but you can't describe what people like Efren do to the cue ball with math :D

I wonder if they programmed a computer like Deep Blue to play pool if it will be able to play with artistic ability or just play pin point shape.
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Actually, you can describe every single tiny movement of the cue ball, whether struck by Efren, anyone else, or a robot, with math. Perhaps I should say *one* can do it. I can't.

I think what you meant to say way "I don't know enough about physics and math to try and describe what people like Efren do to the cue ball"

Just sayin...

KMRUNOU
 
elvicash said:
I reckon the cloth both the natural resistance and also humidity will have another large effect also cloth cleanliness
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This. All those things add up to overcome the inertia of the cue ball, and the frictional force dragging the ball to a halt.
 
thintowin said:
does anybody believe that there is anything OTHER than these three responsible for setting the cue ball in motion?

What are they? What is YOUR opinion?
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As someone else already mentioned, the *magnitude* of the impact vector, which is essentially the velocity of the cue (already mentioned), and the MASS of the cue. The NET impact vector magnitude would also be a function of the compressibility and coefficient of restitution of the tip.

Hope it helps,

KMRUNOUT
 
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whammo57 said:
it's all about the mass of the ass and the angle of the dangle!!!

Stop dissecting everything down into tiny details and just shoot the dam ball. If the shot doesn't go in the hole ............ make an adjustment and shoot it again. Keep trying until you can make it..........

Then practice

LOL

KIm
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He Kim, one of the cool things about humanity is that we all have our own unique interests. You clearly don't share the same interests as the original poster. It sounds like you are advocating that he/she only hold important the things *you* hold important. Is this right?

KMRUNOUT
 
CreeDo said:
I'm guessing where you're going with this is -
Some people believe the damnedest things about what makes the cue ball do what it does.

"Extra follow through makes it travel further"
"Turn the tip sideways at the end for extra sidespin"
"Snap the tip downward at the end for bonus draw"
"With the right brand of chalk, deflection goes away and you can spin the ball more accurately"
"The inlays are gonna affect the hit"
"With a different butt you'd have more precise draw"

and so on.
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OH NO, those aren't true???????
randyg:rolleyes:
 
Great! So now the question I have is, "which of these can the player modulate to change the cue ball trajectory?"

The collection so far is:

ball mass
vector contact duration
coefficient of friction of tip to ball
coefficient of friction of cloth
elasticity of tip restitution
humidity

I think that the player has little to no control over these things from shot to shot, assuming the same equipment is used. Vector contact duration probably isn't going to change all that much on average between normal game shots. Coefficient of friction of tip to ball will remain the same assuming you chalk between each shot. Coefficient of cloth, elasticity of tip, and humidity don't change very much between shots.

Next:

deceleration
rate of deceleration (jerk)
effective end mass

This is interesting. I am going to go ahead and say that since the impact duration probably won't change too much, the deceleration, and jerk, won't affect the cue ball trajectory. My reasoning is that momentum is mass times velocity; the acceleration is embedded in the force of the collision, which occurs as in impulse in a short period of time. Also, I understand that for a longer impact duration, the tip can hug onto the cue ball and move it laterally a small distance, but this is negligible I believe. Accelerating through the cue ball is still a boilerplate rule, but I think accelerating keeps the cue moving in a straight line, and decelerating makes the cue deviate from the straight line. Correct me on this.

Effective end mass can be modulated by changing the bridge length, and this changes the amount of squirt.

Finally:

angle
speed
spin

Randyg agrees. Speed is velocity magnitude. The components of angle and spin are cue ball surface contact point, and angle/pitch.

So.... the things that a player can modulate that have a significant affect on cue ball trajectory is...

1) tip position
2) tip angle/pitch
3) velocity
4) bridge length

Now my point....

If these four physical attributes are responsible for making the cue ball move, then would you agree that high attention and awareness should be made to these, ABOVE ALL OTHER ATTRIBUTES?
 
Other vectors?

1. Aiming vector
2. Good stroke vector
3. Fundamentals vector
4. Confidence vector
5. Your share of the rolls vector
6. Enough barrels to play more than 1 or 2 sets vector
7. I could go on and on vector, but I'm not sure what a vector is

Pool is one tough game, but I just want to keep on hittin' em. Hard to beat the times you overcome it all and get in dead stroke.
 
CreeDo said:
I'm guessing where you're going with this is -
Some people believe the damnedest things about what makes the cue ball do what it does.

"Extra follow through makes it travel further"
"Turn the tip sideways at the end for extra sidespin"
"Snap the tip downward at the end for bonus draw"
"With the right brand of chalk, deflection goes away and you can spin the ball more accurately"
"The inlays are gonna affect the hit"
"With a different butt you'd have more precise draw"

and so on.
Click to expand...

Yes I'm going there kind of, lol :)
 
nrhoades said:
Effective end mass can be modulated by changing the bridge length, and this changes the amount of squirt.
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Of all the hopes and dreams that could possibly change effective end mass, bridge length isn't one of them.

Now if you can change tip contact time, then you can change effective end mass. But, you'd have to be a robot or some other non-human linkage, which I assume you are not.

Freddie <~~~ can't believe we still talk about this
 
Cornerman said:
.... Now if you can change tip contact time, then you can change effective end mass. ...
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You can change tip contact time by using a harder or softer tip. The time goes as roughly the the square root of softness, so a tip that's twice as hard will have a 30% shorter contact time. The theory says, however, that contact time has no big effect on squirt. I think Predator may have done some experiments on this. I know they tested various hardnesses for break cues but I'm not sure they looked at squirt at the same time.
 
Bob Jewett said:
You can change tip contact time by using a harder or softer tip. The time goes as roughly the the square root of softness, so a tip that's twice as hard will have a 30% shorter contact time. The theory says, however, that contact time has no big effect on squirt. I think Predator may have done some experiments on this. I know they tested various hardnesses for break cues but I'm not sure they looked at squirt at the same time.
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To not further confuse the confused, assume the poster (nrhoardes) was discussing "what can you change while playing."

Keeping all things the same, changing tip contact time while not change the tip is absolutely within the current theory of what effects squirt, especially if the contact time is of abnormally greater values like 200% or more as I suggested.
 
Cornerman said:
... Keeping all things the same, changing tip contact time while not change the tip is absolutely within the current theory of what effects squirt, especially if the contact time is of abnormally greater values like 200% or more as I suggested.
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I must have missed a previous post. How were you imagining getting that much of an increase? Can you explain how that would increase squirt? Without a mechanism to get the increase, it's hard to see the connection.
 
Bob Jewett said:
I must have missed a previous post. How were you imagining getting that much of an increase? Can you explain how that would increase squirt? Without a mechanism to get the increase, it's hard to see the connection.
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That's what I was saying, Bob. Unless you (the poster) was a robot, it wasn't going to happen.
 
Cornerman said:
Of all the hopes and dreams that could possibly change effective end mass, bridge length isn't one of them.
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Actually, you could be right about this. I thought that effective end mass was highly influenced by the last 1/3rd of the shaft, where the other 2/3rds are negligable. I would think that by introducing your bridge hand to the last 1/3rd, you would be modifying the end mass slightly via changing the resonant frequency of the end of the shaft. Dr. Dave showed that squirt changes as you move the pivot point.

But you are right in that I don't think many players delibrately change the length of their bridge in order to change where the cue ball ends up, from shot to shot. Maybe some do, I don't know.
 
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nrhoades said:
I set up some background to lead into my main question:

I want to see arguments against WHY tip position accuracy should NOT be the defining conscious effort of the pool stroke, and why YOU think anything else matters more.

I.e. if you could pick one, do you think you would play better with perfect stroke speed or tip position precision? Pick one!
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I think hitting the cue ball accurately is paramount if you expect the ball to do what you want......but it's not the only factor.
 
OK guys, good. I set up some background to lead into my main question:

I want to see arguments against WHY tip position accuracy should NOT be the defining conscious effort of the pool stroke, and why YOU think anything else matters more.

I.e. if you could pick one, do you think
 
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