tangent line
- Thread starter berlowmj
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http://www.engr.colostate.edu/~dga/pool/normal_videos/index.html
Some of these videos might help.
Some of these videos might help.
Well......
The tangent line is the line at a ninety degree angle to the shot. All things being equal, a stun shot on the OB will send the CB off on the tangent line. You can use the tangent line and that path as a starting point on knowing where the CB should go. From there you can adjust with varying english to get anywhere on the table. If you use follow or draw, the harder you hit the ball the longer the CB will travel along the tangent before the draw or follow take effect. It will follow a parabolic curve traveling along the tangent line. The softer you hit it the sooner the ball's spin will bite into the felt and react.
Jay swanson when asked how to achieve great pool, said "Find center Ball". Understanding how to use the tangent line is tantamount to understanding how to find center ball and use it to your advantage when planning shots.
I can illustrate it with words all day long, but I can help you to understand it better with five minutes of demonstration than with a 200 page book.
berlowmj said:
The tangent line is the line at a ninety degree angle to the shot. All things being equal, a stun shot on the OB will send the CB off on the tangent line. You can use the tangent line and that path as a starting point on knowing where the CB should go. From there you can adjust with varying english to get anywhere on the table. If you use follow or draw, the harder you hit the ball the longer the CB will travel along the tangent before the draw or follow take effect. It will follow a parabolic curve traveling along the tangent line. The softer you hit it the sooner the ball's spin will bite into the felt and react.
Jay swanson when asked how to achieve great pool, said "Find center Ball". Understanding how to use the tangent line is tantamount to understanding how to find center ball and use it to your advantage when planning shots.
I can illustrate it with words all day long, but I can help you to understand it better with five minutes of demonstration than with a 200 page book.
The tangent line
If a cue ball is sliding at the time it contacts an object ball at an angle (i.e. on a cut shot not a center-to-center impact), the cue ball will travel in a line tangential to the point of impact between both balls the tangent line. Because Billiard balls are somewhat elastic, the resulting tangent line is slightly less than 90 degrees from perpendicular to a line formed by the contact point between the balls.
If the cue ball hits an object ball at an angle and has follow on it, the cue ball will first travel on the tangent line and then parabolically arc forward from the tangent line in the direction of cue ball travel. By the same token, when such impact is made and the cue ball has draw on it, the cue ball will first travel on the tangent line and then parabolically arc backward from the tangent line in the opposite direction of cue ball travel. Whether follow or draw is on the cue ball, the faster the cue ball is traveling at the moment of impact, the farther it will travel on the tangent line before arcing forward or backward.
If a cue ball is sliding at the time it contacts an object ball at an angle (i.e. on a cut shot not a center-to-center impact), the cue ball will travel in a line tangential to the point of impact between both balls the tangent line. Because Billiard balls are somewhat elastic, the resulting tangent line is slightly less than 90 degrees from perpendicular to a line formed by the contact point between the balls.
If the cue ball hits an object ball at an angle and has follow on it, the cue ball will first travel on the tangent line and then parabolically arc forward from the tangent line in the direction of cue ball travel. By the same token, when such impact is made and the cue ball has draw on it, the cue ball will first travel on the tangent line and then parabolically arc backward from the tangent line in the opposite direction of cue ball travel. Whether follow or draw is on the cue ball, the faster the cue ball is traveling at the moment of impact, the farther it will travel on the tangent line before arcing forward or backward.
those are all great, until you realize there are heavy and light cueballs, AND heavy and light object balls. eg, sometimes the 8 ball will be replaced with a new one cus it got stolen, and all the other balls are 10 years old.... etc, etc, ..... now you know why pros almost always play conservative position, ie you dont see them hitting 3 inches away from a pocket on purpose, they know about the variations (at least instinctively). this is why they will hit a ball seemingly very bad at times too.
A common shot is an object ball between the corner and side pocket slightly off the rail with the cue ball aligned to shoot this ball into the corner pocket at an angle (not straight in shot).
Say you are standing at the end of the table and the OB is on your left on the other side of the side pocket slightly off the rail.
Now make an "L" with your left hand. Hold your thumb straight out to the right and the first finger next to your thumb straight forward. This is 90 degrees.
Now point your finger over the object ball and to the corner pocket. Your thumb will be pointing 90 degrees which is along the "tangent line" for the above shot into the corner pocket.
Shoot the above shot with stun which is a sliding cue ball and the cue ball will go "sideways" or 90 degrees from the line to the pocket.
You can use a striped ball instead of a cue ball so you can see that the ball is in fact sliding at the time it hits the object ball. (I use a measles cue ball.)
I always say with this shot, if you want the cue ball to go forwards after the shot, use follow (hit CB above center). If you want the CB to go sideways, use stun or a sliding ball (hit CB center if CB close to OB or varying amounts below center depending on distance CB is from OB), and if you want the CB to come backwards after the shot, use draw. (Following through after shooting the CB is what will give you follow, stun, or draw.)
Say you are standing at the end of the table and the OB is on your left on the other side of the side pocket slightly off the rail.
Now make an "L" with your left hand. Hold your thumb straight out to the right and the first finger next to your thumb straight forward. This is 90 degrees.
Now point your finger over the object ball and to the corner pocket. Your thumb will be pointing 90 degrees which is along the "tangent line" for the above shot into the corner pocket.
Shoot the above shot with stun which is a sliding cue ball and the cue ball will go "sideways" or 90 degrees from the line to the pocket.
You can use a striped ball instead of a cue ball so you can see that the ball is in fact sliding at the time it hits the object ball. (I use a measles cue ball.)
I always say with this shot, if you want the cue ball to go forwards after the shot, use follow (hit CB above center). If you want the CB to go sideways, use stun or a sliding ball (hit CB center if CB close to OB or varying amounts below center depending on distance CB is from OB), and if you want the CB to come backwards after the shot, use draw. (Following through after shooting the CB is what will give you follow, stun, or draw.)
berlowmj said:
Simply go to the Dr. Dave's website and search for what you're asking about if the link doesn't work: http://www.engr.colostate.edu/. There is a wealth of information on his site and it is all free (although he does have a book and dvd available). He has explainations and video examples of all. Dr. Dave also writes a monthly column for Billiard Digest and those articles are published on the sight as well.
Good luck. You have received excellent advice on the tangent line in this thread.
Dave
"90 degree rule" & "30 degree rule"
You can think of the tangent line as the "90 degree rule" - the CB caroms (ricochets) off the OB at 90 degrees to the OB's path when hit with stun (no follow or draw). Others have described this "rule" in more detail - I want to mention another one that's almost as useful: the "30 degree rule".
When the CB hits the OB about half full (a half ball hit) and rolling naturally, it will take a path off the OB at 30 degrees to the CB's original direction (the same angle the OB takes in the opposite direction). Most people can estimate this angle roughly by spreading their index and middle fingers as far apart as possible. [INTERESTING NOTE: After a naturally rolling half ball hit, the CB and OB will travel about the same distances.]
There are other similar methods for estimating the CB's path after hitting an OB at any angle. Look through Bob Jewett's articles in Billiards Digest to learn them.
pj
chgo
You can think of the tangent line as the "90 degree rule" - the CB caroms (ricochets) off the OB at 90 degrees to the OB's path when hit with stun (no follow or draw). Others have described this "rule" in more detail - I want to mention another one that's almost as useful: the "30 degree rule".
When the CB hits the OB about half full (a half ball hit) and rolling naturally, it will take a path off the OB at 30 degrees to the CB's original direction (the same angle the OB takes in the opposite direction). Most people can estimate this angle roughly by spreading their index and middle fingers as far apart as possible. [INTERESTING NOTE: After a naturally rolling half ball hit, the CB and OB will travel about the same distances.]
There are other similar methods for estimating the CB's path after hitting an OB at any angle. Look through Bob Jewett's articles in Billiards Digest to learn them.
pj
chgo
Well said Jaden. The only thing I would add is that sidespin has no effect on the path of the CB, until it contacts a cushion (unless the topsin or backspin was struck off-center of the vertical axis, which would ADD english). Only top or bottom spin affect tangent line. As mentioned, stroke speed is the great equalizer! 
Scott Lee
www.poolknowledge.com
Scott Lee
www.poolknowledge.com
Jaden said:
yeah that is definitely something thsat people would need to know...
Yes it's important to know that side spin will not affect the path until it hits a rail. I would've included that if I had actually wrote the 200 pages. LOL....
By understanding that side spin doesn't affect the path until it hits a rail, it is much easier to understand where it will go when trying to avoid hitting other OB's on the table. If the natural path with the tangent has the CB hitting a rail and then hitting another OB, you can use the side spin to avoid hitting that OB and getting to where you need. Or the opposite is true also. If you need to break out balls, as is often in eightball or 14.1, and the natural path doesn't take the CB toward those balls, you can use side spin and the natural path to send the CB into those balls to break them up.
Excellent pool comes with knowledge and ability. The ability comes from practice; unfortunately, in most cases and with most people, the knowledge will not come from practice alone and it is always best to pick the minds of the better players. Too often, however, the better players don't know how they're doing what they're doing and you need to find someone with both the knowledge and the ability or even just the knowledge. You don't have to be able to execute on a world class level to have world class knowledge.
The only problem with that though is that there are many people out there who claim to have knowledge that have a LOT of erroneous information. It's hard to weed through it all and sometimes you have to just practice with all of the information that you can get and figure out what really works on your own or learn from a reputable source that you can trust. That's why it is always better, if you can, to find someone with the knowledge and the ability. Scott Lee, Joe Tucker, etc.. are good starting points, and if money is an issue all of the books by robert Byrne are definitely good starting points.
Scott Lee said:Well said Jaden. The only thing I would add is that sidespin has no effect on the path of the CB, until it contacts a cushion (unless the topsin or backspin was struck off-center of the vertical axis, which would ADD english). Only top or bottom spin affect tangent line. As mentioned, stroke speed is the great equalizer!
Scott Lee
www.poolknowledge.com
Yes it's important to know that side spin will not affect the path until it hits a rail. I would've included that if I had actually wrote the 200 pages. LOL....
By understanding that side spin doesn't affect the path until it hits a rail, it is much easier to understand where it will go when trying to avoid hitting other OB's on the table. If the natural path with the tangent has the CB hitting a rail and then hitting another OB, you can use the side spin to avoid hitting that OB and getting to where you need. Or the opposite is true also. If you need to break out balls, as is often in eightball or 14.1, and the natural path doesn't take the CB toward those balls, you can use side spin and the natural path to send the CB into those balls to break them up.
Excellent pool comes with knowledge and ability. The ability comes from practice; unfortunately, in most cases and with most people, the knowledge will not come from practice alone and it is always best to pick the minds of the better players. Too often, however, the better players don't know how they're doing what they're doing and you need to find someone with both the knowledge and the ability or even just the knowledge. You don't have to be able to execute on a world class level to have world class knowledge.
The only problem with that though is that there are many people out there who claim to have knowledge that have a LOT of erroneous information. It's hard to weed through it all and sometimes you have to just practice with all of the information that you can get and figure out what really works on your own or learn from a reputable source that you can trust. That's why it is always better, if you can, to find someone with the knowledge and the ability. Scott Lee, Joe Tucker, etc.. are good starting points, and if money is an issue all of the books by robert Byrne are definitely good starting points.
I think I know what you mean here, but just to be sure here's how I'd say it:
Draw with sidespin will change the draw angle the CB takes off the OB because of the masse effect of hitting downward with sidespin. (I don't think this effect occurs to nearly the same degree with follow because there's so little downward force on the CB.)
pj
chgo
well oif you get technical, swerve makes a difference too.
Swerve can make a difference too, but again this is for people to generally understand the tangent line and how important it is. You'll note that I didn't get into heavier balls, etc.. either, because for the discussion it could be too much information too fast, and would be counter productive. If someone is truly interested in finding the fine points of tangent line use, the best way is to be aware of the general concepts and practice with it and note the differences that occur. Most people don't know what a parabolic curve is, but once they practice drawing and following with varying speeds they'll quickly get an idea of what it is.
I'm only six away from 1000 posts. I think I'll hit 1000 today for sure.
Patrick Johnson said:
Swerve can make a difference too, but again this is for people to generally understand the tangent line and how important it is. You'll note that I didn't get into heavier balls, etc.. either, because for the discussion it could be too much information too fast, and would be counter productive. If someone is truly interested in finding the fine points of tangent line use, the best way is to be aware of the general concepts and practice with it and note the differences that occur. Most people don't know what a parabolic curve is, but once they practice drawing and following with varying speeds they'll quickly get an idea of what it is.
I'm only six away from 1000 posts. I think I'll hit 1000 today for sure.
As always, AZers are generous with sage & explicit advice. These posts should keep me locked in the basement until the early morning hours. Now that I recently got my own table ($700 unfinished antique Brunswick Madison) my stroke has significantly improved, but I am frequently unable to predict the precise path of the CB. Perhaps I can now move to the level where most of you are ie. measuring runs in racks rather than balls.
Please let me take this opportunity to express my deepest appreciation.
Please let me take this opportunity to express my deepest appreciation.
Jaden said:
You can't control where a thread goes - it has a life of its own. You just have to trust that those with an interest can find the info they need and not be confused by the rest. I say the more info the better, as long as it's accurate - let the reader decide how much of it is useful.
pj
chgo
Jaden said:
i personally think what jay meant by this is that you gotta be able to hit the middle of the cueball accurately, no matter how hard or soft you are hitting. i dont think he was emphasizing tanget line philosophy.
anyway, i disagree with you all, i guess that's ok. "sidespin has no effect on the path of the CB, until it contacts a cushion" this would be true if there were no friction between balls. sidespin changes (ie has an effect) the speed a cb comes off an ob, and changes the angle too (however slightly). if you disagree, don't furiously type a response.... instead do one of 2 things (preferably both).
1-go talk to a guy like buddy hall or cliff joyner and ask if sidespin has an effect on the cueball path (yes even b4 it hits the rail)
2-set up a long shot where you are almost strait in, ie u have a slight cut. now, let's say you are cutting the ob slightly to your right, BUT you need to follow the cueball as much to the right as possible (ie, you want minimum deflection to the left, you need to stay as far right as possible). so, soft follow this shot with all different englishes (high center, high left, high right) and tell me which one you were able to achieve the farthest to the right position..... you'll need to mark each cb position after you shoot, you'll NEED TO PHYSICALLY MARK IT. you'll also need to do it at least 5 times with each english, the more the better. there won't be very much variation between all the results, but i think you'll find you'll consistentely be able to get to the furthest point right as possible (when you hit it good), with one particular english.
the reason you need a long shot is so hitting different parts of the pocket doesn't have too much effect, AND more importantly, try to follow very near the same amount each time, andd even more importantly, un-bias your mind (ie, don't be looking for any particular result). i think the results will surprise a lot of people. tell me what happens!
Ok....
I wasn't saying that Jay was emphasizing anything with the statement. I do think that he meant that the less spin you use the better able to control the CB and the more consistent you'll be. Of course there are exceptions, but in most cases you WILL be more consistent using less english. I use some side spin on most shots, so I am not one to talk, but it works for me and I understand that I could be more consistent, negligably IMO, if I were to use less spin and rely more on natural shape. There are some cases where you can't get the shape you may need, but you should only use the extreme spins when either the safety is just as difficult as the shot, or the next shot is not makeable at all without using extreme English for shape.
I also stated that I was giving basic information and that I could write about it in 200 pages, I was not being facitious. I literally could write 200 pages about the tangent line and the things that interact with utilizing it. Yes, on slow shots or hard shots side spin can and does affect the line coming off of the ball, and from greater than certain angles, collision induced throw will have some affect in lessening the angle as well. If everyone wants I can go into extreme detail as to what I believe is going on and the ways that you can use the tangent line and adjust for various items.
I use the tangent line for kicking and it works great for me. People will watch me line up for a difficult kick and then kick it in and walk up to me and ask me what I was doing. When I reply that I was looking at the tangent line, most people say ok and move on. These are sometimes strong players that don't go any farther in asking what I'm doing than to hear that I am looking at the tangent line. Some may know the benefit of doing so and some may not, but most overlook it.
I would have to go into great detail about many a subject to explain what I'm doing that allows my kicks to be so accurate. The basic thing I do though is look at the tangent line. The Tangent can be extremely useful in more ways than one is all I'm saying.
enzo said:
I wasn't saying that Jay was emphasizing anything with the statement. I do think that he meant that the less spin you use the better able to control the CB and the more consistent you'll be. Of course there are exceptions, but in most cases you WILL be more consistent using less english. I use some side spin on most shots, so I am not one to talk, but it works for me and I understand that I could be more consistent, negligably IMO, if I were to use less spin and rely more on natural shape. There are some cases where you can't get the shape you may need, but you should only use the extreme spins when either the safety is just as difficult as the shot, or the next shot is not makeable at all without using extreme English for shape.
I also stated that I was giving basic information and that I could write about it in 200 pages, I was not being facitious. I literally could write 200 pages about the tangent line and the things that interact with utilizing it. Yes, on slow shots or hard shots side spin can and does affect the line coming off of the ball, and from greater than certain angles, collision induced throw will have some affect in lessening the angle as well. If everyone wants I can go into extreme detail as to what I believe is going on and the ways that you can use the tangent line and adjust for various items.
I use the tangent line for kicking and it works great for me. People will watch me line up for a difficult kick and then kick it in and walk up to me and ask me what I was doing. When I reply that I was looking at the tangent line, most people say ok and move on. These are sometimes strong players that don't go any farther in asking what I'm doing than to hear that I am looking at the tangent line. Some may know the benefit of doing so and some may not, but most overlook it.
I would have to go into great detail about many a subject to explain what I'm doing that allows my kicks to be so accurate. The basic thing I do though is look at the tangent line. The Tangent can be extremely useful in more ways than one is all I'm saying.
