Hit a pure stop shot and you will.....SPF=randyg
So the CB slides after impacting the OB?
modifying the tangent line
- Thread starter berlowmj2
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Hit a pure stop shot and you will.....SPF=randyg
So the CB slides after impacting the OB?
holy crap, someone stop KMrunout, he's on a spampage!
Just kidding. We agree on most stuff and I like your posts. You ever play with the multiquote button, to the right of quote? Do it for all the posts you wanna address, clicking it once per post. It should turn blue. Now just click quote on any message anywhere and all those blue-button posts will be quoted. Good times.
Just kidding. We agree on most stuff and I like your posts. You ever play with the multiquote button, to the right of quote? Do it for all the posts you wanna address, clicking it once per post. It should turn blue. Now just click quote on any message anywhere and all those blue-button posts will be quoted. Good times.
Just a coupla things to clear up here.
1) A tangent line is not an abstract thing. It is linear thus predictable.
2) When KMrunout says that two circles are not needed to create
a tangent line he is correct. A circle drawn on a flat surface
with a line tangent to that circle is complete.
3) What is abstract is that when two 3-dimensional balls strike,
that tangent line behaves like a plane. ALL OTHER THINGS BEING
EQUAL (no friction, no english, no skid, no squirt, in a vacuum) the
CB will not follow the tangent line but will bounce of the OB at the same angle as it hit the OB (the angle of reflection is equal to the angle of incidence.) We redirect the angle of reflection of the CB by applying
English (or whatever secrets we might have) so it goes where we want
it to go.
Now this is pretty good info. because you can create a tangent line with the length of your stick behind the OB perpendicular to the line to the pocket and get a pretty good idea how the CB is going to come off of the OB to see if it's going to scratch , etc. unless you adjust with some sort of wizardry.
Most of the experienced players know this stuff. You see them use it all the time. I just wanted to show the up and comers that there is some practical use to what seems like a lot of hot air from wanna be intellectuals
ME INCLUDED IN THAT. You gotta not only know what works you gotta know why so you can use it for different but similar situations.
My wife is dragging me away from the keyboard so I gotta stop. I know you all want me to keep going but she 's the boss.
1) A tangent line is not an abstract thing. It is linear thus predictable.
2) When KMrunout says that two circles are not needed to create
a tangent line he is correct. A circle drawn on a flat surface
with a line tangent to that circle is complete.
3) What is abstract is that when two 3-dimensional balls strike,
that tangent line behaves like a plane. ALL OTHER THINGS BEING
EQUAL (no friction, no english, no skid, no squirt, in a vacuum) the
CB will not follow the tangent line but will bounce of the OB at the same angle as it hit the OB (the angle of reflection is equal to the angle of incidence.) We redirect the angle of reflection of the CB by applying
English (or whatever secrets we might have) so it goes where we want
it to go.
Now this is pretty good info. because you can create a tangent line with the length of your stick behind the OB perpendicular to the line to the pocket and get a pretty good idea how the CB is going to come off of the OB to see if it's going to scratch , etc. unless you adjust with some sort of wizardry.
Most of the experienced players know this stuff. You see them use it all the time. I just wanted to show the up and comers that there is some practical use to what seems like a lot of hot air from wanna be intellectuals
ME INCLUDED IN THAT. You gotta not only know what works you gotta know why so you can use it for different but similar situations.
My wife is dragging me away from the keyboard so I gotta stop. I know you all want me to keep going but she 's the boss.
this thread quickly turned to angels sitting on the head of a pin
The real "lines" are why sidespin does matter very slightly and can be taken advantage of on certain shots under certain conditions. Consider a dot on the surface of a cue ball. When we shoot a shot with sidespin this dot is moving in a spiral or helix. At the contact point with the object ball the surface of the cue ball is moving in an arc, not a straight line. We have two lines also, the line of force set up by the collision between the cue ball and the object ball, and the path the footprint of the cue ball is actually traveling down. These two paths are roughly an inch and an eighth apart and they are not truly parallel.
Force never just disappears, it all has to be accounted for. The theory that all of this force is converted to force along the path of the cue ball only slowing it down or speeding it up is convenient however it isn't 100% accurate because there simply isn't anything happening mechanically to cause this to happen. Nothing constrains the force from the spin to only follow this one new line perfectly matching the new direction of the cue ball. Indeed, that awkward little inch of leverage dictates this is impossible to happen.
We can consider the tangent line going through the contact point, release point, or center of the cue ball, it doesn't matter. We still have to account for the center of gravity being an inch and an eighth away or we have to account for the force from the spinning cue ball being an inch and an eighth away. These things don't disappear even with pure sidespin. Add the effect of hitting down on the cue ball and this increases the effect of the spin but even without hitting down spin would still have an effect.
When all is said and done I still say [30889798095990854089855998595797507.8750479 to the sixth power] angels can sit on the head of a pin.
(one or two would have a butt cheek hanging over the side)
Hu
The real "lines" are why sidespin does matter very slightly and can be taken advantage of on certain shots under certain conditions. Consider a dot on the surface of a cue ball. When we shoot a shot with sidespin this dot is moving in a spiral or helix. At the contact point with the object ball the surface of the cue ball is moving in an arc, not a straight line. We have two lines also, the line of force set up by the collision between the cue ball and the object ball, and the path the footprint of the cue ball is actually traveling down. These two paths are roughly an inch and an eighth apart and they are not truly parallel.
Force never just disappears, it all has to be accounted for. The theory that all of this force is converted to force along the path of the cue ball only slowing it down or speeding it up is convenient however it isn't 100% accurate because there simply isn't anything happening mechanically to cause this to happen. Nothing constrains the force from the spin to only follow this one new line perfectly matching the new direction of the cue ball. Indeed, that awkward little inch of leverage dictates this is impossible to happen.
We can consider the tangent line going through the contact point, release point, or center of the cue ball, it doesn't matter. We still have to account for the center of gravity being an inch and an eighth away or we have to account for the force from the spinning cue ball being an inch and an eighth away. These things don't disappear even with pure sidespin. Add the effect of hitting down on the cue ball and this increases the effect of the spin but even without hitting down spin would still have an effect.
When all is said and done I still say [30889798095990854089855998595797507.8750479 to the sixth power] angels can sit on the head of a pin.
(one or two would have a butt cheek hanging over the side)Hu
The "contact" point is at moment of collision. In the case of heavier cue balls, the "release" point may be a point deeper or past the point of original collision. I don't know what other word to use to describe this effect.....SPF=randyg
good advice but . . .
Good advice but not if you are using the old skin. I occasionally do multi-quotes the hard way cutting and pasting from multiple windows but it's a pain in the rear. Dang, now I have to at least consider the other skin I don't like the looks of because it offers a real advantage. I tried it once before and it went away, I guess those of us that started with monochrome and DOS have a hard time adapting!
Hu
Good advice but not if you are using the old skin. I occasionally do multi-quotes the hard way cutting and pasting from multiple windows but it's a pain in the rear. Dang, now I have to at least consider the other skin I don't like the looks of because it offers a real advantage. I tried it once before and it went away, I guess those of us that started with monochrome and DOS have a hard time adapting!
Hu
That's the traditional wisdom, but I believe that sidespin, when combined with follow or draw, can affect the post-impact direction of the CB far more than the OB itself...in some cases. We're not talking about cue elevation, i.e., masse, or mini-masse type shots.
There are two ball-to-cloth surface speed elements that determine the CB's final roll direction: its translational velocity along the tangent line, and that derived from follow/draw spin. You can further divide the spin contribution to ball-cloth surface speed into two sub-components: one along the CB-OB line of centers at impact, and one along the tangent line. During a collision, ball-ball friction doesn't act democratically on all three, and I think it's somewhat safe to assume that its effect on the second spin sub-component is essentially negligible.
So the three components come away from the collision with different relative values than going in. Sidespin, namely inside english, can be used to "re-align" them, so to speak. There's a fairly simple way of determining how much of it to use on any given shot, but the point is that the CB's final roll direction can be affected far more than the object ball's direction, at least according to my math. The cases where this become significant are at modest cut angles when you're trying to "pull/push" the CB off the tangent line by a moderate amount.
I'm not trying to pick on your statement Creedo, since most of us tend to operate under the working assumption that sidespin doesn't have much effect until the CB reaches a cushion. But I think received wisdom has some notable exceptions, as per above.
Jim
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This is some great advice. I have a habit of becoming interested in a thread and kind of posting as I read through it. I will have to do what you say, since it seems for more efficient!
btw I like reading your posts too!
thanks,
KMRUNOUT
You said a mouthful here. First of all, the concept of a tangent is very much an abstract concept. This is because you don't have to have a tangent line in front of you, or existing anywhere at all, in order to talk about what a tangent line is and how it is calculated. In fact, almost all of mathematics involves abstract concepts. When you happen to encounter an example of one of those concepts, the *example* is concrete, but the concept is still abstract. Take one plus one equals 2. You don't need to have two things in front of you to understand this. The concept does not depend on concrete physical reality, though it is *exemplified in* concrete reality. Perhaps this definition of the word "abstract" would help further clear things up:
ab·stract [adj. ab-strakt, ab-strakt; n. ab-strakt; v. ab-strakt for 10–13, ab-strakt for 14] Show IPA
–adjective
1. thought of apart from concrete realities, specific objects, or actual instances: an abstract idea.
2. expressing a quality or characteristic apart from any specific object or instance, as justice, poverty, and speed.
3. theoretical; not applied or practical: abstract science.
Also, while the concept of the tangent line describes a line (and this line is "linear" lol), it is not the fact that it is linear that makes it predictable. Many predictions are based on curves.
Thanks for the support
I recommend this exact method to my teammates for estimating the tangent line if they have trouble "seeing it". Good call.
KMRUNOUT
Gotcha Randy. That makes sense. I wasn't actually thinking of the heavy ball (and am happier when I never have to think about it lol!!)
Still this imagery seems to imply that the heavy ball is in contact with the OB for a longer period of time than the regular weight cue ball, which assuming they both have the same hardness seems unlikely. I think perhaps the 90 degree rule is only in effect when the objects are of equal mass. If they are not, then by definition there is no 90 degree rule, and it becomes some other angle of divergence, different from 90 degrees in proportion to the differences in ball masses. This make any sense? (I'm pretty sure it does in the world of physics?)
KMRUNOUT
I'm with you on this.
The 90 degree tangent line is a given but to have the CB track that line with a sliding stop shot, with a little below the center of the CB hit, is to me, not as repeatable as the tangent line implies.
More practice.
Thanks.
The harder you hit the same contact point on a cut shot the more the ball gets cut....
Yes, that's true. If the balls have different mass, or the collision is not elastic, then there is no expectation of a 90 degree tangent line.
Also , "tangent line" doesn't really have to do with a circle. Imagine the path of the cueball left a mark on the table, like a chalk mark. That path is a curve, and at any point on the curve, there is a tangent line. That tangent line at that point is what you would get if you put a straight line (like a ruler) up to the curve and matched the slopes. THE tangent line, in pool, is how the ruler points right at contact: it is the direction of travel for the first millimeter, or the first fraction of a millimeter, etc.
Second. Remember that the Tangent Line is from the release point not the contact point....SPF=randyg
So if Randy is saying the release point creates tangent line and you're saying the contact point creates the tangent line then one of you has to be incorrect....am I right?
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Predictions based on non-linear data are modeling (educated guesses) and cannot be modeled to infinity. At some point on the curve non-linear chaos blooms after which predictions are useless.(ie. weather predictions longer than a week.)
What was the question , again?
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Jason. to call a person a pussy is a demeaning but not naughty word
It actually is short for: pusillanimous
(pyoo-suh-LAN-uh-muhs)
adjective
Lacking courage; timid. [From Latin pusillus (weak, very small
When you stop to think of what that other thing you were thinking of goes
through I would hardly call it pusillanimous.:groucho:
It actually is short for: pusillanimous
(pyoo-suh-LAN-uh-muhs)
adjective
Lacking courage; timid. [From Latin pusillus (weak, very small
When you stop to think of what that other thing you were thinking of goes
through I would hardly call it pusillanimous.:groucho:
Actually Bill, we both are correct. In most cases the contact is the release point. But you already know that....
SPF=randyg