Quick quiz by Sharivari

[David in FL]

The tangent line is defined like this:

1. Draw a line through the center of the OB to the pocket.
2. Draw a line perpendicular to the line in #1.

Note that the tangent line is completely independent of where the CB is. Therefore, the tangent line cannot change unless the OB moves.

Thanks. Of course, that’s right.

For some reason I just wasn’t visualizing it right.

 

[atlas333]

Your posts are mind breaking.

I just put him on ignore. That makes 3 on my list

 

[Black-Balled]

I just put him on ignore. That makes 3 on my list

Doing so denies your you the opportunity to repeatedly be encouraged by the fact you aren't like him, or him.

 

[7stud]

The one with shortening the banks when hitting harder I've heard some top players say that is generally true, except when super hard they can start to lenghen again. IDK though from my own ewperincecies its inconclusive to me (the super hard hit).

I think they say that because they believe that banking long or short has to do with how the cushion compresses, and they've come up with some theory that for very hard banks the cushion bottoms out causing the bank to go long. With good video, we now know that long v. short is determined by whether the OB is sliding into the cushion or rolling into the cushion. If a ball slides into the cushion it will bank shorter, and if a ball rolls into the cushion it will bank longer. The reason is that the spin of a rolling ball causes it to curve long after it hits the cushion. There is some good footage showing that effect in "A Pool Lesson with Jerry Briesath" (DVD 2, 19:00 minutes). A ball will slide into the cushion if it is close to the cushion when it is struck, or if the ball is far from the cushion and it is struck hard. Note that there is a range of spin between sliding and fully rolling, which affects how much the ball will curve after it hits the rail.

Jerry Briesath also says that old cloth will rub off more spin when a rolling ball hits the cushion, so old cloth won't bank as long as new cloth. Furthermore, he says that a rolling ball that hits the cushion at a shallower angle, e.g. diamond 6 to diamond 3 is shallower than diamond 4 to diamond 2, will bank still longer yet--because when a rolling ball hits the cushion closer to its axis of rotation, less spin is rubbed off.

I think that in regards to a hard v. a very hard bank, both balls will be sliding into the cushion, therefore they will bank to the same spot.

 

[justnum]

You don't want to be comparing his output to yours...

He would run you over if you played.

It felt like a trolling instructional video to start discussion on the lack of language conventions for popular pool actions.

 

[Jimmorrison]

I think he makes a couple of errors. Anyone?

Okay Bob, spill it.

 

[Tennesseejoe]

I do not think the problem is understanding of the material, but not conveying the information accurately. Developing test questions can be difficult...Try it.

 

[Jimmorrison]

English is not his native language.

 

[eastcoast_chris]

I got them all correct, but I was very careful to try to understand exactly what he was asking since his wording is a little funny.

First question was probably the most oddly worded one. And also the one about cutting with left. I got that right, but mis-understood the question a bit... and I think what he was asking/saying isn't totally correct on that one.

 

[sixpack]

I believe the tangent line is defined like this:

1. Draw a line through the center of the OB to the pocket.
2. Draw a line perpendicular to the line in #1 (which goes through a ghost ball that is behind the OB, touching the OB, and centered on the line in #1).

Note that according to that definition, the tangent line is completely independent of where the CB is. Therefore, the tangent line cannot change unless the OB moves. I think you could argue that depending on which part of the pocket you are aiming at, the tangent line does change slightly--because the angle of #1 would change.

And that is only spin-induced throw. Deflection might change where you aim as well depending on your cue and how much off center you aiming, as well as whether you use backhand English or not.

 

[Black-Balled]

It felt like a trolling instructional video to start discussion on the lack of language conventions for popular pool actions.

Only your preconceived agenda would make such a determination.

 

[Bob Jewett]

Question 1: The tangent line changes when... the object ball is moved. This takes a little thinking but his explanation makes it clear -- if you know what a ghost ball and a tangent line are and how they relate to each other. I hope everyone here has those last parts covered. This is a good question to ask beginners when you are teaching them tangent line to see if they understand. I think I'll steal it.

Question 2: When banking the ball very hard, you must play ... [longer or shorter]. He has this one partly wrong. The correct answer for the shot he shows is "play for more angle" which means longer. Banks shot at high speed tend to go short. The reason I call this partly wrong is that if the object ball is close to the rail -- so close it does not pick up significant forward roll on the way to the rail -- the bank angle is independent of speed. This is easy to demonstrate. See Byrne's "Advance Technique" for a simple demo.

Question 3: How can this shot be made directly into the pocket? (90-degree "cut" of a frozen ball) Playing rail first with inside spin is an absolutely standard shot. You might quibble that the shot is somehow not "direct". He avoided calling it a "cut" shot -- it is a kick shot. You might also quibble that the shot can be made under some conditions with outside english but that shot is horrible hard.

 

[Black-Balled]

English is not his native language.

Thanks.

Dear America: thank your lucky stars you don't have to communicate in another language.

 

[Bob Jewett]

Question 4: How can you make this (frozen) combination shot? The answer is to use cut-induced throw and hit the ball on the player's left side. Maybe Sharivari could have included more explanation, but this is a quiz, not a lesson. It is amazing how many pretty good players don't know this effect exists. In the 14.1 league I played in, the best player (108-and-out his best run in league) did not know about such combos.

Question 5: You want to make the 8 ball into the blocked pocket. I think either soft follow or medium center ball are reasonable answers. I think follow at soft to medium speed will get the most accurate hit on the blocking ball. The problem with using center ball on this kind of shot for a lot of people is that a little unintended side spin will be multiplied by the time the cue ball gets to the object ball. Playing with follow tends to reduce the effect of the side spin. (Some players think of two-length speed -- lag shot -- as very soft. That's about the speed you want to use.)

Question 6: The cue ball will move on the tangent line for a period of time when... (draw, stun, follow, all) The correct answer is stun, not "all". If you use draw or follow the cue ball never travels in a straight line along the tangent. It begins curving immediately. I suppose you could call zero seconds a period of time, but I think that ignores what is actually happening. It is correct to say, "The initial direction of the cue ball off an object ball is along the tangent line when....",

 

[Bob Jewett]

Question 7: When hitting as low as possible on a straight shot, the cue ball will ... (stop, follow, draw, not certain) This is a concept many beginners get wrong. When a ball doesn't draw, they immediately think they didn't get any draw. The demo with draw disappearing from a stripe used as the cue ball is a great way to show the dissipation of draw.

Question 8: When hitting this ball very soft with outside english, the ghost ball should aim towards ... (center of pocket, full, thin, don't know) I think his answer -- full -- is mostly wrong. With the angle he shows, it is common to have something like gearing side spin which means that the ball will not be thrown in either direction. It is also possible to have side spin but less than gearing side spin which means you have to aim thin compared to the ideal ghost ball. This question is like Question 7. He could have said "heavy" side spin. There is another problem mentioned above that you have squirt to consider. It seems Sharivari includes compensation for that as part of the aiming to the ghost ball process, and he may also include swerve.

 

[Bob Jewett]

Question 9: When playing a follow shot into the rail, the rotation on the cue ball will ... (reverse, stay the same, be lost, depends) His answer -- stay the same -- is just plain wrong on tables with worn cloth. His demo is with a cue ball with hyper-follow due to all of it's forward motion being taken up by an object ball. That is a "banana shot" or a "double the rail" shot. I don't think that's what the question is about. If the cue ball is rolling smoothly on the cloth and goes straight into the rail, such as for a lag shot, the cue ball will come off the cushion with almost zero spin. That's for worn cloth. On brand new cloth, if you watch a stripe going straight into the rail, you can see that it has a little rotation left over as it comes off the rail then it slides and finally starts rolling in the new direction. This is an easy way to see how slippery the cloth is. After a week or to you don't see that retention of spin and the ball looks "normal" as it comes off the rail. I think on very sticky cushions, the follow actually reverses a little on the nose of the rail and the cue ball comes off the rail partly rolling already.

Question 10: When playing this shot with medium speed, the cue ball will ... (standard corner-5 test shot) I'm surprised he doesn't mention that he is playing with running side -- I think everyone shoots this test with running side, but I could be wrong. On new cloth the cue ball will go the short-rail side of the pocket (called "long"), and with sticky cloth, it will go to the long-rail side of the pocket (called "short"). He qualifies the question with "on most tables", but I have seen many tables where "diamond 2" doesn't work. I think without the running side the shot will go long.

 

[ChrisinNC]

Question 4 - Yes, I’m amazed how many very good rotation players aren’t aware of how much this shot can actually be thrown in when you have 2 frozen balls, as long as you can get the cue ball to a half ball hit on the correct side of the first object ball.

 

[Black-Balled]

Question 4 - Yes, I’m amazed how many very good rotation players aren’t aware of how much this shot can actually be thrown in when you have 2 frozen balls, as long as you can get the cue ball to a half ball hit on the correct side of the first object ball.

There is a prop shot where shooter makes the 2nd ball in a spot lineup by throwing it in.

Rubbing chalk on ___is the trick.

Not telling___coz I might need it for dinner someday.

 

[7stud]

Question 6: The cue ball will move on the tangent line for a period of time when... (draw, stun, follow, all) The correct answer is stun, not "all". If you use draw or follow the cue ball never travels in a straight line along the tangent. It begins curving immediately. I suppose you could call zero seconds a period of time, but I think that ignores what is actually happening. It is correct to say, "The initial direction of the cue ball off an object ball is along the tangent line when....",

Thanks a lot for posting your reviews of the answers, Bob. In particular, I had to read this one a couple of times because it was contrary to what I believed was true. I mistakenly believed that the harder you hit the CB with draw or follow, the longer the CB stayed on the tangent line before curving. I think I induced that from Dr. Dave's article on Peace Sign Subtleties:

See how the hand shifts along the tangent line going through the center of the ghost ball? But that is only an ad hoc method for determining the final direction of the CB. Dr. Dave shows the actual paths in his article 90° and 30° Rule Follow-up:

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Those diagrams don't necessarily show the CB moving further along the tangent line for higher speed shots--but when I initially looked at them, my preconceived notions had me seeing the harder shot moving further along the tangent line before curving.Thanks for setting me straight!

 

[Bob Jewett]

... Those diagrams don't necessarily show the CB moving further along the tangent line for higher speed shots--but when I initially looked at them, my preconceived notions had me seeing the harder shot moving further along the tangent line before curving.Thanks for setting me straight!

All of the curved lines are curved from the start. It is not so apparent with the curves that are broader. It is a common mistake to think the initial path is a straight line. The shape of the curve is a parabola and those don't have flat spots.

That having been said, the path with draw/follow is initially a straight line if the cue ball has left the table. If you jack up and hit a draw cut shot hard you can get the cue ball to bounce forward. If you view that path from above, it looks straight until the cue ball lands and then it takes a jog, and if it keeps bouncing, you get a series of jogs rather than a curve. But that's a totally different situation. And the initial path is forward of the tangent line.