transmitting side??

[RGCirencester]

Spin transmits to the ball when two are set in a plant. Im not sure about reverse plants, but certainly when you have two balls directly in front of the pocket, hitting with backspin you can pot both, because it gives the first ball topspin. Hitting with topspin you can get the second ball to stay in the jaws of the pocket.

[DandyA]

Walter Lindrum believed side could be transmitted & demonstrated by placing the red near the left top pocket & playing an in-off using left hand side which made the red come off the cushion at a wide angle, playing from the exact same spot, he used right hand side which made the red come off at a narrower angle. He left it up to the scientist to prove him right or wrong. Whether this is throwing the ball or tranmitting side to cause the different line of travel is still baffling us after all these years.
I must watch some slow mo on this

I haven't seen that video (or was it film in thoe days davipp but that sounds like spin induced throw to me which clearly does occur - you see the pros use it occasionally and even I can do it!

[poolqjunkie]

Some of the rotational energy does pass onto the object ball, but should that mean that the object ball should slow down or increase its velocity because of the backspin on the cueball? It doesn't now does it?

Actually it shows.

Try to play a carom (two balls frozen with the tangent line pointing to the pocket) but with the tangent line between the balls pointing a bit to one side of the jaw of the pocket.

You can control the final path of the ball whether it will go into the pocket or not with top/bottom.

If you play it with top, the object ball will move a bit more toward you/backward(bottom); if you play it with bottom, the object ball will go a bit more forward (top).

About whether the surface between the balls are too smooth for friction to transfer, first of all, no surface is frictionless.

Whether it is significant, I want to ask you if you have seen a ball spinning by itself in American 9 ball after the break. When you break a rack of 9 ball real hard, afterwards one of the object ball keeps spinning on the table. If the surface friction between the balls are not causing it, what is?

There is a slow motion video showing the transfer, but it is only for a very short time.
http://www.youtube.com/watch?v=oJSVW...eature=related

[poolqjunkie]

Dandy A, I am confused.
What is spin induced throw?
Is that a way of side spin being transferred from the cue ball to the object ball?

[DandyA]

First of all, the energy doesnt get lost, it simply cannot get lost it just goes from one form to another.

yep I agree, although energy can be converted to sound or other things, but I think we're all agreed on the conservation of energy ...

The kinetic energy is passed from the cue onto the cueball and onto the object ball. Now the cueball has a certain amount of kinetic energy, and part of the kinetic energy is this rotational energy. So, by hitting the side of the cueball, its gets angular velocity. But the question is how strong this rotational energy should be to have an influence on the object ball considering the smooth surface?

I don't disagree but I'd rephrase it ... "how much rotational energy is transferred" ... and my answer is I believe very little - apart from spin induced throw which is presumably more the effect of friction between the balls and the cloth as opposed to the ball to ball friction ...

The thing about friction is not doubtful at all, and the reason why the ball is going backwards is because of the table cloth. When you play the screw shot, the cueball doesnt spin forwards, the ball spins around its axis backwards (rotational energy) so most of the rotation is maintained, but the ball slides on the cloth forwards because of the linear kinetic energy, so when it finally collides with the object ball, the forward momentum is lost, but the ball is still spinning backwards, so once it "grips" the cloth it starts to spin backwards. Some of the rotational energy does pass onto the object ball, but should that mean that the object ball should slow down or increase its velocity because of the backspin on the cueball? It doesn't now does it?

yep, the cue ball comes backwards because it's rotational energy is still maintained during and after contact with the onject ball ... so it is still rotating backwards and as you said, grips the cloth and then moves backwards ...

probably the clearest example of this is the power follow (top spin shots) the pros can do ... the cue ball hits the object ball, stops as the linear momentum is killed, grips the cloth and then shoots forward at a huse rate of knots ...

now if the cue ball had transferred a significant amount of it's rotational energy to the object ball, it simply could not do this could it?

[RGCirencester]

This guy seems pretty convinced, if you skip to the last 30 secs or so of the video he demonstrates. From listening to him he seems to think the spin on the ball is more because of the throw than because if friction.
http://billiards.colostate.edu/norma...new/NVA-21.htm
Again this is 9 ball though.

[DandyA]

This guy seems pretty convinced, if you skip to the last 30 secs or so of the video he demonstrates. From listening to him he seems to think the spin on the ball is more because of the throw than because if friction.
http://billiards.colostate.edu/norma...new/NVA-21.htm
Again this is 9 ball though.

yep great vid RG, well worth watching ... although with my old and ancient eyes, I can't see one way or the other whether the object ball picks up any significant right hand side ...

don't suppose you know how to play it back frame by frame so I can have a really good look? or if Dr Dave has a 1250fps version showing the transfer?

and as you say, this is American 9-ball and he makes a specific point of saying he uses an Aramith cue ball and an Elephant object ball (whatever that is) ... dunno if it's relevant but he does make a point of saying that!

[RGCirencester]

I think the object ball is just a training ball with a stripe on it. I think it does spin, though i am not sure of the degree of side that is transfered. It makes sense to me though. The reason the deflection of the object ball due to side is called throw is because the side effectively "throws" the object ball off line. This would surely impart some side spin as well.
I do think its worth noting though that even with a gap between balls, you can pot both balls on a straight plant by using backspin, as the first ball hit continues forward (due to topspin) into the pocket after colliding with the ball nearest the pocket.

Cueball----->Red----->Red----->pocket

Thats my lazy attempt at a picture... its late

[DandyA]

I think the object ball is just a training ball with a stripe on it. I think it does spin, though i am not sure of the degree of side that is transfered. It makes sense to me though. The reason the deflection of the object ball due to side is called throw is because the side effectively "throws" the object ball off line. This would surely impart some side spin as well.
I do think its worth noting though that even with a gap between balls, you can pot both balls on a straight plant by using backspin, as the first ball hit continues forward (due to topspin) into the pocket after colliding with the ball nearest the pocket.

Cueball----->Red----->Red----->pocket

Thats my lazy attempt at a picture... its late

yep, completely agree with that RG ... although it seems instant to the human eye, the cue and object balls are in contact for a finite and not insignificant amount of time during which (in the vid shown) the left hand side on the cue ball throws the object ball to the right and must transfer some side as well ...

there's no doubt about throw ... but what I'm not convinced about is whether the amount of side transferred is significant ...

your example is good though and should prove it one way or the other ... bottom on the cue ball should transfer to top on the first red ... will try that next time I'm at the snooker club!

[lkomarci]

probably the clearest example of this is the power follow (top spin shots) the pros can do ... the cue ball hits the object ball, stops as the linear momentum is killed, grips the cloth and then shoots forward at a huse rate of knots ...

now if the cue ball had transferred a significant amount of it's rotational energy to the object ball, it simply could not do this could it?

well that's still all regarding the cueball, so yes, this shows that the cueball has preserved enough rotational energy to continue travelling forward after the collision.


Anyway, I'm not disputing that the cueball doesn't transfer rotational energy, but does it transfer an amount that would actually have a more significant effect on the object ball, besides one at microscopic levels.

Perhaps it's true about those new ball materials i dunno, i'm not a pro or anything but it does sound a bit too far stretched

[DandyA]

Anyway, I'm not disputing that the cueball doesn't transfer rotational energy, but does it transfer an amount that would actually have a more significant effect on the object ball, besides one at microscopic levels.

Perhaps it's true about those new ball materials i dunno, i'm not a pro or anything but it does sound a bit too far stretched

yep iko, completely agree with your comments ... my whole problem is that with the Aramith Tournament Champion snooker balls the pro's play with, and as you said, no significant side is transferred simply because the cue ball still maintains most of it's side after hitting the object ball ... if, for instance, the cue ball transferred 100% of it's rotational energy to the obhect ball, the cue ball could have none left ... this clearly isn't true ...

but also as you say, ball materials have changed over time ... so I for one certainly don't know the varying effects of ivory, polyester, crystallite, super crystallite, phenolic balls ...

if you look carefully though, you often see the pro's (I was looking out for it today at the Welsh Open) put side on the cue ball to throw the object ball but I can't say I've ever seen them put side on it to induce the opposite side on the object ball ... but maybe I'm wrong!

[Mike P]

As a few have pointed out, top and bottom spin can be transferred to an object ball. So why would side not have the same effect. As to it’s relevance, I can’t think of a shot situation similar to the one mentioned for the use of top or bottom, where side need be considered.

There are slow motion tapes on the market by Bob Jewett shooting various shots. The tape is title the Jacksonville Project and their experiments showed that some side spin is transferred.

For those interested in the finer points of ball collisions he has some interesting material. Here is an attachment to some of his articles.

http://www.sfbilliards.com/articles/BD_articles.html

Also this is pertains more to throw but I think it is amazing. The set up has the cue ball near the green pocket, straight in line with the brown into the side. On a pool table mind you, Jewett cuts the brown back into the yellow corner pocket without a masse!! Fast forward to the 2 minute mark to see him make it.

http://www.youtube.com/watch?v=GaSKh...eature=related

Mike

[poolqjunkie]

Dandy A, I dont believe anyone has ever said that the cue ball would transfer a lot of its spin to the object ball, and certainly not all its spin. Not sure why you keep trying to proof that point.

As a matter of fact, me and all those who believe that spin can be transferred all have been saying that the transfer of spin is of a small amount, yet significant enough to change the path of the object ball.

The pool balls you see on TV are made by Aramith and same are the tournament snooker balls.

Perhaps the weight of the ball has something to do with how much spin can be transferred and in the old days, as we should all agree, the balls were heavier. I am not sure. I think almost all pool players will tell you spin can be transferred but snooker players seem to differ in opinion. I think perhaps the radius of the ball also make a difference.

But the surface of the cue ball is not too smooth for the transfer to take place, that is for sure. Just look at how a ball can be thrown and how top and bottom can be transferred.

You seem to agree that spin can be transferred to the object ball to alter its path if I understand you correctly, (i.e. applying left to the cue ball and cause the cue ball to travel to the right) and yet you do not seem to be convinced that the spin transfer is significant. I do not understand this.

"Throw" is a kind of spin transfer from the cue ball to the object ball. If you agree that "throw" exist, then how could you not agree that spin can be transferred?

The transfer is more pronounce when there are lots of spin and very little slide on the cue ball. You can really alter the path of the object ball when you hit the ball soft.

This transfer is used all the time in making bank shots (double) when the angle needs to be changed.

The video I showed you is an extreme example of that.

If you do not believe the balls were made because of transferred spin, could you please describe in your own word why the ball dropped?

[ace man]

Anyway, I'm not disputing that the cueball doesn't transfer rotational energy, but does it transfer an amount that would actually have a more significant effect on the object ball, besides one at microscopic levels.

Of course side is transferred. It is used very often in pool for bank shots (called 'double' in snooker). You can make banks which seem impossible.

The fact is, there's friction between two balls that collide. The spin has to transfer, even if very little...barely a few rotations per second, maybe even less. Even this is enough to alter the path of the object ball when it rebounds of the cushion, especially at slow speed. Find some good 9ball players in your area and they should be able to demonstrate the effect with bank shots.

[poolqjunkie]

I would also suggest trying to wet the contact area between the balls and then play a shot with side, or even just draw to see the difference friction between the balls would make.