Side spin does not transfer

[Colin Colenso]

Felt friction is a major contributor, without it the outcome would be different.

Anyway, I am describing what happens in the real world for pool player. What to take notice of that can change the shot. eg. Side spin and running english are not the same. The earlier thread stated side spin which is what I tried to go back and to clear up.

What I mean, is that if the OB were sitting on 1" square cushion of air at the collision point, we would get the same result.

Side spin, after it has moved across a cloth and develops rolling forward rotation, is essentially the same a running english shot, though the ratios of side to rolling english can vary.

But there can be two balls rolling down a table, with identical properties of speed and spin, one of them struck with running english, the other initially struck with center or even low english.

 

[Bob Jewett]

There was an earlier post were I made a comment about side spin not transferring from CB to OB. I couldn't find it and remember several players and instructors attempted to say I was incorrect. This has bugged me but I didn't have a chance to respond.
... .

For anyone who still cares about this thread.... The object ball does acquire side spin from the cue ball. It can be due to either collision-induced throw or side spin on the cue ball. I proposed a bank test/challenge to demonstrate this in the earlier thread. Lots of other demos exist. Any skilled player who banks balls routinely uses transferred side spin. People who understand physics know immediately that if there is throw, there must be transferred side. The quantity of transferred side is not huge, but it is more than enough to cause bank shots to miss.

If someone wants to call transferred side "twist" instead, that's fine, since it is a common term in banks. If he refuses to acknowledge that the object ball in fact has side spin, I think there is no good reason to try to change his mind. He may be led to other false notions as well, but who does it really hurt?

Also, the material that the object ball is sitting on does not significantly effect the amount of transferred side. Or at least that's what physics predicts, for those who believe in physics.

 

[pharaoh68]

I can't believe this is actually even being debated. Its a basic principle of physics.

 

[pete lafond]

For anyone who still cares about this thread.... The object ball does acquire side spin from the cue ball. It can be due to either collision-induced throw or side spin on the cue ball. I proposed a bank test/challenge to demonstrate this in the earlier thread. Lots of other demos exist. Any skilled player who banks balls routinely uses transferred side spin. People who understand physics know immediately that if there is throw, there must be transferred side. The quantity of transferred side is not huge, but it is more than enough to cause bank shots to miss.

If someone wants to call transferred side "twist" instead, that's fine, since it is a common term in banks. If he refuses to acknowledge that the object ball in fact has side spin, I think there is no good reason to try to change his mind. He may be led to other false notions as well, but who does it really hurt?

Also, the material that the object ball is sitting on does not significantly effect the amount of transferred side. Or at least that's what physics predicts, for those who believe in physics.

I fully understand collision induced spin. This topic has nothing to do with that. This topic was in reference to side spin on the CB in a direct hit and that it does not cause side spin on the OB. Instead a twist occurs causing top right or top left English. Please review page 1 where there is an illustration. This topic evolved somewhat.

This topic is not about throw, squirt, curve... just side spin as the topic heading indicates. The reason for my post was for clearification.

 

[CaptainJR]

I fully understand collision induced spin. This topic has nothing to do with that. This topic was in reference to side spin on the CB in a direct hit and that it does not cause side spin on the OB. Instead a twist occurs causing top right or top left English. Please review page 1 where there is an illustration. This topic evolved somewhat.

This topic is not about throw, squirt, curve... just side spin as the topic heading indicates. The reason for my post was for clearification.

Pete
I think we all must be confused. I really can't figure out what you are talking about. I'm not going to talk about throw, squirt, curve.

I'm only talking side spin. When you put side spin on the cue ball, it in turn puts side spin on the object ball. The only way this could not happen is if you had the two of them coated with some kind of slippery substance (pun intended) that keep the friction very very low. It just must happen. No if's and's or butt's.

 

[jsp]

Pete, Pete, Pete. You're the person that is making me break my Lenten fast of not posting a single post until Easter. I tried my best to resist, but the temptation of this thread is far too great...

I've been following this entire thread very closely, and your arguments are both wrong and grossly inconsistent.

What happens with side spin is that the combination of the spin plus the friction of the felt in front of the OB ball causes the OB to twist. The OB gets thrown forward with this twist which now has top right or top left English spin on it.

You make sense in this post, but for arguments sake don't jumble the two together. Keep them separate, because the friction of the felt and the side spin of the CB affect the OB on two different axes. The side spin of the CB imparts side spin on the OB, which rotates the OB about the vertical axis. The friction of the felt imparts roll on the OB, which rotates the OB about the horizontal axis. Like you said, the resulting "twist" is just the combination of these two effects.

If you take away the friction component of the felt (as the Calc has previously mentioned), all you have left is a moving OB with pure side spin (imagine hitting balls on a blanket of ice). So back to the original question...does side spin on the CB transfer side spin on the OB. The answer is YES! The twist you're talking about is just the result of adding another spin component about another axis.

If you still argue that the felt is a "major contributor" to your argument that side spin does NOT get transferred to the OB, then how can you justify saying that...

In my original statement, I stated that a CB spinning sideways does not cause the OB to spin sideways. Only the rails and balls hit at an angle can cause this (this is why cross banks work).

So as I stated the only way the CB can cause an OB to spin left or right is through contact on an angle.

These statements are grossly inconsistent to your previous arguments. How can these cases (collision induced spin) be any different than the case we have been talking about? The OB is still traveling on the same friction-full felt, so wouldn't the OB eventually start to twist if you give the felt enough time to grab? So shouldn't you argue that because of twist, side spin cannot be transferred to the OB in ANY case?

Just think of hitting a soft cut shot on a striped ball, with the stripe oriented horizontally. From your arguments, the cut angle DOES indeed impart side spin on the OB. But the OB won't spin like a top all the way to the pocket. The felt will eventually grab the OB and the it will have a rolling component on top of the (very) slight sideways spin. By looking at the eventual twist of the OB, can you still argue that the CB imparted side spin on the OB? To be consisted with your previous arguments, I hope you answer no.

So neither can a cue impart side spin to the CB, since the CB will eventually twist once the felt has time to grab hold of it. Hence from your arguments, absolutely nothing can impart side spin on the OB. Do you see where I'm getting at?

 

[5aheadforpinks]

Sorry if this was covered already, couldnt bring myself to read every post; but... If you line up 2 balls on the spot and shoot with draw from just a slight angle, it transfers follow to the object ball in front to push through and go into the pocket (ie the one pocket spot shot).

If follow and draw can be applied to the object ball, obviously side spin can too.

 

[TATE]

It exists and it's the "gear effect" caused by friction.

The reason why it didn't transfer in your tests is probably because you weren't hitting the object ball straight on. Most likely you were squirting the cueball over to the wrong side of the cueball nullifying the spin.

The amount of spin imparted on the object ball is pretty weak. Banks show it because any spin at all on a bank has a big effect.

There are very few shots this effect makes much difference on, but banks are the big ones.

Chris

 

[uwate]

can someone tell me why it really matters???

you have shot you need to make, and you have a position you need to attain........do it.

if it transfers spin or if it just twists.......you make the shot and get position.

why argue? just seems like to much over analyzing on the computer and not enough playing on the table.

VAP

Totally agreed. This is way too technical. Twist or transfer,the bottom line is to understand where the balls will go when you hit whitey with english. This thread kinda reminds me of when I was a student at Cal-Berkeley. I am playing in the Student Union and on the next table over these two electical Engineering students (EEKs we called them) were sitting there discussing how to hit a combination shot. Once goes something like "First you apply counter clockwise rotation and the sphere will have a rotational axis of X degrees and you need to line up the collision between both spheres at this juncture points...blah blah blah".

I just about feel on the floor laughing. These guys couldnt run two balls with BIH.

 

[jsp]

Totally agreed. This is way too technical. Twist or transfer,the bottom line is to understand where the balls will go when you hit whitey with english. This thread kinda reminds me of when I was a student at Cal-Berkeley. I am playing in the Student Union and on the next table over these two electical Engineering students (EEKs we called them) were sitting there discussing how to hit a combination shot. Once goes something like "First you apply counter clockwise rotation and the sphere will have a rotational axis of X degrees and you need to line up the collision between both spheres at this juncture points...blah blah blah".

I just about feel on the floor laughing. These guys couldnt run two balls with BIH.

Excuse me! I was an electrical engineering major in college and I sure the hell can run two balls with BIH!

Three balls, however, is a different story.

 

[pete lafond]

This thread got off a little. The point I am making is the same one I made in a previous post of a different thread I could not find.


Not talking throw or curve. The statement was very simple as follows;

If you hit a CB directly into an OB (no angles here) with side English, it will NOT transfer that English to the OB where the OB will now spin with side English.

I got flack for this because many did not understand this. What I am clarifying for every one is that the OB will spin as shown in the diagram below. The OB gets "twisted" which is a term used in pool which simplifies all the physics and calc that would otherwise describe it.

I was told this by Babe Cranfield years ago when I started playing pool. I notice these things because I pay attention to the OB when I shoot. It is important to know because this is part of pool we rely on to play excellent safes, make tough shots and improve opportunities.

Yes conditions do change these things which is why it is important to understand them and be able to adjust.

See below.

 

[pete lafond]

forgot my "see below"

 

[Bob Jewett]

... If you hit a CB directly into an OB (no angles here) with side English, it will NOT transfer that English to the OB where the OB will now spin with side English.
...

Actually, some side spin is transferred with a full collision, just not an overwhelming amount. You can get as much side on the object ball with a direct hit and side as with collision-induced side.

Even champions get this simple fact wrong.

It's easy to demonstrate.

 

[pete lafond]

Actually, some side spin is transferred with a full collision, just not an overwhelming amount. You can get as much side on the object ball with a direct hit and side as with collision-induced side.

Even champions get this simple fact wrong.

It's easy to demonstrate.

So you are saying the first diagram stated "No", you mean it should say "Yes" on a direct hit?

 

[fred_in_hoboken]

So you are saying the first diagram stated "No", you mean it should say "Yes" on a direct hit?

A video showing precisely that has been linked several times already:

http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-84.htm

On each shot of the 3 shots, there is transfer of vertical axis spin. On the medium and fast shots, the object ball moves off screen with only vertical axis spin. Only on the slow shot does the object ball pick up horizontal axis spin (ie, begin "twisting")

 

[Jal]

forgot my "see below"

The first diagram shows the state of affairs immediately after the balls seperate. The second one shows the state of affairs after the object ball has traveled down the cloth some, with one slight correction. The object ball will not be traveling straight ahead but at a small angle with respect to straight ahead, because of throw from the cueball's sidespin. The amount of spin the object ball picks up is always equal to 5/2 of its sideways throw velocity (actually its spin rate multiplied by its radius is equal to this velocity component).

If the object ball threw but didn't spin, this would be a violation of an important principle of physics, the conservation of angular momemtum. If you manage to come up with a test which shows that the object ball is thrown yet acquires no spin, the Nobel Committee will be contacting you shortly thereafter.

But I admire your stand, Pete.

Jim

 

[pete lafond]

The first diagram shows the state of affairs immediately after the balls seperate. The second one shows the state of affairs after the object ball has traveled down the cloth some, with one slight correction. The object ball will not be traveling straight ahead but at a small angle with respect to straight ahead, because of throw from the cueball's sidespin. The amount of spin the object ball picks up is always equal to 5/2 of its sideways throw velocity (actually its spin rate multiplied by its radius is equal to this velocity component).

Right the ball is being twisted and you are framing the actions simply because it would be otherwise impossiible to magically change without motion. I was never referring to throwing the ball or a double hit. Balls must be spaced enough for a legal straight on shot.

The bold is what counts. How much twisted it becomes is up to the shooter.

If the object ball threw but didn't spin, this would be a violation of an important principle of physics, the conservation of angular momemtum. If you manage to come up with a test which shows that the object ball is thrown yet acquires no spin, the Nobel Committee will be contacting you shortly thereafter.

This paragraph is well out of the limits of the discussion. I believe my stand is that the OB does not travel with side spin based upon the CB transferring it on a direct hit. Rather it has a more diagonal one until that spin expires and goes into a natural roll in which case it becomes useless to the shooters objective of having required English.

Keeping things simple allows the player to better understand what is going on. It is that simplified knowledge that makes it easier to perform and execute shots with improved execution.


Thanks

 

[Skeezicks]

Or at least that's what physics predicts, for those who believe in physics.

Physics (and the idea of physics) is not incompatable with my personal mythology. That's about as far as I'm willing to go.

 

[Peer]

Bob Jewett wrote:
> The object ball does acquire side spin from the cue ball. [...]
> ...that's what physics predicts, for those who believe in physics.

fred_in_hoboken wrote:
> A video showing precisely that has been linked several times already:
> http://tinyurl.com/mw3ye

pharaoh68 wrote:
> I can't believe this is actually even being debated.
> It's a basic principle of physics.


Yes, it's a basic principle of physics -- and when several other chipped in with similar comprehensive posts, it's mind-boggling that Pete Lafond still insists sticking to his theory that there's "no side english transfer" from a spinning cue ball. But as Bob Jewett said, who does it really hurt if this guy is led to false notions... and frankly, it wasn't that long ago the earth was flat...

-- peer

 

[enzo]

Yes, it's a basic principle of physics -- and when several other chipped in with similar comprehensive posts, it's mind-boggling that Pete Lafond still insists sticking to his theory that there's "no side english transfer" from a spinning cue ball. But as Bob Jewett said, who does it really hurt if this guy is led to false notions... and frankly, it wasn't that long ago the earth was flat...

-- peer

yeah, i guess you could say what does it matter if he thinks that. that is true. to me this post is an opportunity to decide who im NOT going to listen to from now on, im seriously making a list. the people that say you cant transfer spin to an ob are all on that list, thanks for the useful thread!