The Myth of Top Spin???

[Fragged]

Im refering to the article by Tom Simpson in the May/June Indide Pool Mag, page 26. Has anyone else who's read this article come away with disbelief as I did? Mr Simpson says top spin doesn't exist, that overspin means the cue ball would be spinning faster than it is rolling and THAT DOESN"T HAPPEN! Does anyone believe as I do that Mr simpson needs to make a distinction between natural follow and force follow, where "over spin" does indeed occur. I belive these written remarks coming from a "BCA Master Instuctor" are misleading and ambiguous. Comments anyone?

Ridiculous!! and another definition of force-follow to boot. Everyone knows the shot where a ball is put in each corner pocket and then you hit one with extreme follow and the ball keeps driving itself into the rail (as a result of topspin) and saunters over and makes the ball in the other pocket. I have scene really good player use topspin to stop a ball against the rail when other methods were not available. I say BS to this one.

 

[av84fun]

on a freight train going east at 60MPH, there is always a part of the train that is moving west.

The wheels as they rotate counter-clockwise past 9 o'clock???????????

(-:

 

[av84fun]

Sorry, but this is simply wrong. As has already been correctly described, the CB stops dead (for practical purposes)* when it hits an OB squarely and only its forward spin propels it forward again. This is very well known. As has also been suggested, simply hit the CB into an OB squarely without forward roll (a stun shot) to see that this is true.

pj
chgo

*...and assuming it's about the same weight as the OB...

No it is not wrong. As I have already posted, the CB would never have hit the OB in the first place had it not been caused to roll forward.

You are splitting hairs in the sense that saying, in effect, that no one has ever died because of having jumped off a 20 story building...because it ain't the fall, it's the sudden stop.

Please explain how a CB can resume forward motion without ever having any.

So if you want to get all technical about the matter, the REASONS that the CB resumes forward motion are:
1. Forward motion was imparted prior so as to contact the OB and
2. The angular momentum ....etc.

Or do you think that you can place two balls together by hand...stand back and say "Hooghie boogie" and the CB will start rolling forward???
(-:
Jim

 

[Patrick Johnson]

Everyone knows the shot where a ball is put in each corner pocket and then you hit one with extreme follow and the ball keeps driving itself into the rail (as a result of topspin) and suanters over and makes the ball in the other pocket. I have scene really good player use topspin to stop a ball against the rail when other methods were not available.

Those are examples of the CB "peeling out" on the cloth, but not the "overspin" talked about by Simpson and Byrne. They're talking about hitting the CB with your stick in such a way that it immediately peels out on the cloth without hitting another ball or the rail. What you describe is the same thing the CB does any time it hits an OB squarely with forward roll - it stops and then the forward spin carries it forward again.

pj
chgo

 

[Patrick Johnson]

So if you want to get all technical about the matter, the REASONS that the CB resumes forward motion are:
1. Forward motion was imparted prior so as to contact the OB and
2. The angular momentum ....etc.

"All technical" or not, #1 is still wrong. Only the spin propels the CB forward after hitting the OB squarely and stopping. You can see this happen without forward momentum on extreme masse shots - how does the CB reverse direction?

Or to ask another way (again): why doesn't a CB with no forward rotation continue forward after hitting an OB square (a stop shot)? What happened to its forward momentum?

pj
chgo

 

[av84fun]

Ridiculous!! and another definition of force-follow to boot. Everyone knows the shot where a ball is put in each corner pocket and then you hit one with extreme follow and the ball keeps driving itself into the rail (as a result of topspin) and suanters over and makes the ball in the other pocket. I have scene really good player use topspin to stop a ball against the rail when other methods were not available. I say BS to this one.

That shot does not involve top spin but rather forward roll toward the rail that becomes "draw" when the CB rebounds off the rail in the opposite direction.

All the while, the CB is rotating in the same direction but begins to travel in the opposite direction.

That has nothing to do with "topspin."

Regards,
Jim

 

[ShootingArts]

no but . . .

Hu, do you think it is possible to create as many RPMs on a CB when using follow as when using draw...assuming the pace of the shots are the same?

Regards,
Jim

Jim,

Practically speaking no. Theoretically yes you can put just as much spin on the cue ball in any direction. In the real world we are never able to get more than slight backhand english on a follow shot, often none at all due to the slate and rails, and other balls. Where we hit a cue ball and the direction of the force that we hit the cue ball with both influence spin as well as how hard we hit the ball of course.

As a result, maximum topspin to equal bottom spin can rarely be applied. However bear in mind that the cueball can not squirt away from a tip squarely on top of the centerline of the cue ball so the cue ball can be hit further to the outside on the top than any other position.

I learned my pool from watching the people that were old school players in the early seventies, the old men in the halls then. They thought that follow was used for shape and draw for show. They could draw when that was needed for the shot but they could also force follow so that the cue ball moved a few inches on the tangent line and then zinged forward leaving no doubt that the cue ball still had massive top spin on it. It wasn't a shot used often but they definitely had it in their arsenal. When the situation is right, I use a tightly closed bridge and a lot of topspin to move the cue ball around. Almost invariably if my opponent sees it happen the reaction is "What the hell was that??"

I'll maintain that it is possible to apply massive top spin, when the situation is right. Typically not as much can be used effectively as draw but none of this is because it isn't theoretically possible. You are often somewhat flying the cue ball with draw helping maintain draw and follow lacks this advantage.

Hu

 

[DoubleA]

Quote:
Originally Posted by juanbond
...In a straight-on topspin shot, the CB stops at impact for an infinitesimal time, and the remaining topspin on the CB then causes it to gain forward momentum again. It doesn't proceed forward "due to forward momentum", because that initial forward momentum is almost totally* transferred to the OB during the collision.

I appreciate pure scientific explanations...I genuinely do...but they are not always useful in the act of playing pool.

It is not important to the typical player...including World Champions...to even know the difference between "forward momentum" and "angular momentum" and I suspect that few champions can explain the difference.

In fact, the CB resumes its speed AS A RESULT of the forward momentum imposed on it...because I guarantee you that if there was no forward momentum, it would remain still would have never hit the OB in the first place.


Rather, the angular momentum of the spinning CB is converted into new forward momentum due to the friction against the cloth. This effect can be achieved even with shots hit with very little force. It seems like someone started saying "force follow" just to describe "follow" shots that are hit hard. They are in principle no different from a softly-hit rolling follow shot.
* - some of the CB's initial forward momentum is transferred into sound and heat during the collision.

AGREED.



Right. That may be the tape I recalled seeing but I think you will agree that such OVERSPIN dissipates very quickly and is not a factor in the so-called force follow shot except possibly on rare occasions.

Wouldn't you agree?

Regards,
Jim

There is no forward momentum on any stopped object, a motionless object can only resume motion as a result of an applied force.(the friction between the spinning cb and the cloth)

 

[av84fun]

"All technical" or not, #1 is still wrong. Only the spin propels the CB forward after hitting the OB squarely and stopping. You can see this happen without forward momentum on extreme masse shots - how does the CB reverse direction?

Or to ask another way (again): why doesn't a CB with no forward rotation continue forward after hitting an OB square (a stop shot)? What happened to its forward momentum?

pj
chgo

Please explain how a CB can resume forward motion without ever having any.

Or do you think that you can place two balls together by hand...stand back and say "Hooghie boogie" and the CB will start rolling forward???

Do you think that is wrong for PRACTICAL purposes for someone to say that a man died because he jumped off the roof of a building?

Or that someone died in a plane crash because the wings fell off?

Pool is played with cues not slide rules Patrick.

LOL

And besides

In classical mechanics, momentum (pl. momenta; SI unit kg?m/s, or, equivalently, N?s) is the product of the mass and velocity of an object (p=mv). For more accurate measures of momentum, see the section "modern definitions of momentum" on this page. It is sometimes referred to as linear momentum to distinguish it from the related subject of angular momentum.

Check out the link and you will see that lineral momentum is a FACTOR in the equation for angular momentum...so without one, you do not have the other...without some real hoogie boogie.

http://en.wikipedia.org/wiki/Angular_momentum#Definition

(-:
Jim

 

[av84fun]

There is no forward momentum on any stopped object, a motionless object can only resume motion as a result of an applied force.(the friction between the spinning cb and the cloth)

And there is no applied force causing friction between the spinning cb and the cloth unless there was first forward (linear) momentum....RIGHT?

Jim

 

[Da Poet]

Bob Byrne presents a test to see whether you can get follow that is more than the cue ball rolling smoothly on the table. I think it's in his "Advanced Technique" book. For most situations, including the test he presents, it is impossible to get "excess" top spin on the cue ball.

However....

It is possible to hit the cue ball so far off-center that the some part of the cue ball is actually moving backwards as the cue ball moves away down the table. This is shown on the Jacksonville Project video, which is available on azbtv.com, but I can't find the sequence right now. As I recall, the spin observed was about 115% of the equivalent of smooth rolling.

In general, playing such shots is not practical because any excess follow will be lost on the way to the object ball, there is a serious likelihood of a miscue when you cue that far from center, and because hitting farther off-center gets less power into the cue ball, you actually end up with fewer RPMs by the time the cue ball gets to the object ball.

A related puzzler: on a freight train going east at 60MPH, there is always a part of the train that is moving west. What is that part? Estimate how fast it is moving west.

Sure, solve one problem and start another! lol

Okay, I think we're in sync on the follow thing, however after much pondering, unless it's a trick question, the only part of the train that I know for sure that goes backwards is the inside edge of the wheel that extends beyond the top surface of the rail. How fast it's moving I would have to defer to Supergreenman who I believe is our resident train expert.

 

[av84fun]

Jim,

Practically speaking no. Theoretically yes you can put just as much spin on the cue ball in any direction. In the real world we are never able to get more than slight backhand english on a follow shot, often none at all due to the slate and rails, and other balls. Where we hit a cue ball and the direction of the force that we hit the cue ball with both influence spin as well as how hard we hit the ball of course.

As a result, maximum topspin to equal bottom spin can rarely be applied. However bear in mind that the cueball can not squirt away from a tip squarely on top of the centerline of the cue ball so the cue ball can be hit further to the outside on the top than any other position.

I learned my pool from watching the people that were old school players in the early seventies, the old men in the halls then. They thought that follow was used for shape and draw for show. They could draw when that was needed for the shot but they could also force follow so that the cue ball moved a few inches on the tangent line and then zinged forward leaving no doubt that the cue ball still had massive top spin on it. It wasn't a shot used often but they definitely had it in their arsenal. When the situation is right, I use a tightly closed bridge and a lot of topspin to move the cue ball around. Almost invariably if my opponent sees it happen the reaction is "What the hell was that??"

I'll maintain that it is possible to apply massive top spin, when the situation is right. Typically not as much can be used effectively as draw but none of this is because it isn't theoretically possible. You are often somewhat flying the cue ball with draw helping maintain draw and follow lacks this advantage.

Hu

Right Hu. Byrne, Jewett, aV8 and now Hu agree on that point.

The rather pointless descent (except for engineering students and not pool students) into a discussion of the various forms of momentum is beside the OP's point.

He asked about an article that denied the existence of topspin and whether it played any roll in "force follow" shots. The author was technically wrong about there being no topspin but exactly correct that creating top spin with the cue stick has nothing to do with CB behavior after ob impact.

Regards,
Jim

 

[mullyman]

I will add that finding out that I didn't need to hit so high on the cue ball to get top on medium speed shots was a big help. Hitting just above center to get the ball rolling proved more accurate for me.

You make a good point here that a lot of players don't really know. The higher you get on the cue ball is actually defeating your purpose. Once you get above something like 70% between the center and top of the cue ball you're actually going to get less follow on the cue ball because you're not getting full impact between the tip and the ball. It also helps a lot if you can control your stroke and stroke straight through the ball. Human beings have a natural tendency for the cue to go forward and then down. It feels really strange at first but if you practice a smooth stroke *straight* through the ball you can get great results on your follow stroke.
MULLY

 

[3andstop]

I'd like a stab at adding to the confusion with my interpretation of what happens.

I don't know if there really is or not, but we can think of a CB hit with above center english as having "2" completely seperate forces applied to it.

1. the forward momentum.

2. the circular momentum, whether it equals the forward roll on a 1 to 1 ratio or not.

The second force is an additional force to that of a CB hit with center english. Even if hit very hard, a center ball hit on the CB sends it on its way with forward ("1") momentum but with no ("2") circular momentum. It is merely sliding down the table.

When a center ball hit CB hits an OB fully the equal masses cause a transfer of energy and the OB takes off while the CB stops.

Not so with a CB hit with follow english. This cue ball is not sliding. It is rolling, even if only on a 1 to 1 ratio with its forward movement. It is still a rolling mass, not a sliding mass. The harder you hit it, the faster the circular momentum, still even if only on a 1 to 1 ratio with its forward movement.

When it hits the OB result number 1 still happens and it transfers energy, and stops, but because the circular energy exists now in addition to the forward energy, the CB now resumes forward movement.

The visual of the OB overspinning as it resumes its forward movement is a result of the removal of most or all of the number ("1") momentum by the contact to the OB.

All that is left to be seen with the eye, is the practically full amount of the number ("2") momentum.

Look at it this way. When you force draw a CB, think of how hard you hit it and how hard it reverses direction. The speed of its reverse direction can be compared to the speed of a "rolling forward" CB that was hit with follow.

The forward circular spin doesn't have to be greater that a 1 to 1 ratio in order for the effect to occur, it just has to exist.

 

[ShootingArts]

or you can hit the ball early

You make a good point here that a lot of players don't really know. The higher you get on the cue ball is actually defeating your purpose. Once you get above something like 70% between the center and top of the cue ball you're actually going to get less follow on the cue ball because you're not getting full impact between the tip and the ball. It also helps a lot if you can control your stroke and stroke straight through the ball. Human beings have a natural tendency for the cue to go forward and then down. It feels really strange at first but if you practice a smooth stroke *straight* through the ball you can get great results on your follow stroke.
MULLY

. . . . . or you can simply hit the cue ball early so that the tip of your cue is actually moving slightly upwards when you hit the cue ball. The timing of the hit can make applying draw and follow easier.

Hu

 

[DoubleA]

And there is no applied force causing friction between the spinning cb and the cloth unless there was first forward (linear) momentum....RIGHT?

Jim

Anytime there is motion there is momentum, however, if the cb stops because of contact with the ob it cannot regain the forward motion caused by the push of the stick. The cb is however rotating on it's axis in a forward direction. It is the tendency of the cb to maintain this rotation(inertia) in conjunction with friction from the cloth that causes the cb to begin to move forward once again. A "stopped" object has zero velocity, zero velocity equals zero momentum.

 

[av84fun]

Anytime there is motion there is momentum, however, if the cb stops because of contact with the ob it cannot regain the forward motion caused by the push of the stick. The cb is however rotating on it's axis in a forward direction. It is the tendency of the cb to maintain this rotation(inertia) in conjunction with friction from the cloth that causes the cb to begin to move forward once again. A "stopped" object has zero velocity, zero velocity equals zero momentum.

Thanks but you didn't answer my question...

Originally Posted by av84fun
And there is no applied force causing friction between the spinning cb and the cloth unless there was first forward (linear) momentum....RIGHT?

Do you agree that the cb could not be "rotating on its axis in a forward direction" had it not been caused to move and roll forward in the first place?

And would it be therefore correct to state that the force that INITIATED the whole process was a cue stick striking a CB such that forward and rolling momentum was imparted?

I think that would be true unless there is such a thing as "immaculate angular momentum."

(-:

Regards,
Jim

 

[av84fun]

EXCELLENT post. And congratulations for describing the process without ever using such phrases as linear or angular momentum, the theory of conservation of energy, any of Newton's laws or the meaning of life!!!!

This is Ames Mister.

(-:

Jim

I'd like a stab at adding to the confusion with my interpretation of what happens.

I don't know if there really is or not, but we can think of a CB hit with above center english as having "2" completely seperate forces applied to it.

1. the forward momentum.

2. the circular momentum, whether it equals the forward roll on a 1 to 1 ratio or not.

The second force is an additional force to that of a CB hit with center english. Even if hit very hard, a center ball hit on the CB sends it on its way with forward ("1") momentum but with no ("2") circular momentum. It is merely sliding down the table.

When a center ball hit CB hits an OB fully the equal masses cause a transfer of energy and the OB takes off while the CB stops.

Not so with a CB hit with follow english. This cue ball is not sliding. It is rolling, even if only on a 1 to 1 ratio with its forward movement. It is still a rolling mass, not a sliding mass. The harder you hit it, the faster the circular momentum, still even if only on a 1 to 1 ratio with its forward movement.

When it hits the OB result number 1 still happens and it transfers energy, and stops, but because the circular energy exists now in addition to the forward energy, the CB now resumes forward movement.

The visual of the OB overspinning as it resumes its forward movement is a result of the removal of most or all of the number ("1") momentum by the contact to the OB.

All that is left to be seen with the eye, is the practically full amount of the number ("2") momentum.

Look at it this way. When you force draw a CB, think of how hard you hit it and how hard it reverses direction. The speed of its reverse direction can be compared to the speed of a "rolling forward" CB that was hit with follow.

The forward circular spin doesn't have to be greater that a 1 to 1 ratio in order for the effect to occur, it just has to exist.

 

[Neil]

...............

 

[mbippus]

It seems that if part of the cueball is moving backwards while moving forward that would mean the the cue ball is spinning faster than it is rolling. Which I thought Byrnes said wasn't possible.

Bob Byrne presents a test to see whether you can get follow that is more than the cue ball rolling smoothly on the table. I think it's in his "Advanced Technique" book. For most situations, including the test he presents, it is impossible to get "excess" top spin on the cue ball.

However....

It is possible to hit the cue ball so far off-center that the some part of the cue ball is actually moving backwards as the cue ball moves away down the table. This is shown on the Jacksonville Project video, which is available on azbtv.com, but I can't find the sequence right now. As I recall, the spin observed was about 115% of the equivalent of smooth rolling.

In general, playing such shots is not practical because any excess follow will be lost on the way to the object ball, there is a serious likelihood of a miscue when you cue that far from center, and because hitting farther off-center gets less power into the cue ball, you actually end up with fewer RPMs by the time the cue ball gets to the object ball.

A related puzzler: on a freight train going east at 60MPH, there is always a part of the train that is moving west. What is that part? Estimate how fast it is moving west.