Guess that's further proof you can't make topspin with a cue. Topspin can only occur after the cue ball has struck another ball. Think you can probably also produce a banana effect out of your hand.

Did you manage to find time to experiment with the test, Goring?

Or read the thread all the way through?

To the top for Mr Göring again.  I want to see if he tried out the test.

Thanks very much, sir.

Thanks for reviving the thread once more, AT. 

Alas, hard to believe though it is, it appears interest in the subject has waned somewhat.  A shame because Terry Griffiths and John Virgo were talking absolute nonsense concerning the physics of sidespin yesterday.  I was hoping we might squeeze another four hundred posts out of it.

Good evening AT.

You can transfer a small amount of sidespin to an object ball.  This does not physically cause said ball to cling to a cushion, of course, but an equatorially spinning cueball does sometimes help with shots down the rail in certain circumstances.

When cutting an object ball along the cushion at an angle the usual advice is to hit object ball and cushion at the same time.  In this event, however, a naturally rolling white will throw it slightly into the rail.  Whether or not this deviation will be enough to miss the pocket depends on a few factors: distance to the pocket, cushion trough (see below) etc.


A far better tactic is to strike the cushion a fraction (and I mean a fraction) before the object ball.  And in this endeavour running (inside) sidespin is your ally.  Conversely, if you must aim for cushion and object ball simultaneously, outside sidespin will negate the throw factor.

What is a cushion trough?

When any snooker ball strikes a cushion, the rubber overhang depresses it very slightly into the bed at the point of contact.  Over time the shallowest of channels develop underneath all the cushions (most noticeably along the top rails) and, although imperceptible to the eye, it is often sufficient to keep a ball hugging against the cushion.

Good morning Mr Nibbs.

I have answered that question at some length previously if you would care to have a read through, sir.

As it is a little awkward for me to type at the moment, I'll off you a brief, abridged explanation as an update.

We are dealing with three types of friction and their respective coefficients in this instance: static, sliding and rolling. 

When struck below centre, static friction is overcome and the cueball immediately starts to slide.  The ratio of the coefficients of friction (COF) during this sliding phase is easily within the range allowing the white to also rotate in the opposite direction.  This is backspin.

However, when struck above centre, static friction is once again overcome but the cueball immediately starts to roll.  The far higher COF during this rolling phase dictates the white cannot also rotate in the same direction.  It is not topspin.

I had another lovely photograph to share, but the moderators have denied me once more.

Jamie Cope having a complete nightmare this afternoon.  He's on tilt.

Back to the top for The Chit Chat Detective Agency, if they would be so kind.

It wasn't me btw.

Good evening UTC.

No, sir, all hitting the cueball above centre achieves is to start it rolling naturally instead of sliding.  One cannot, when actioned by a cuetip at least, cause the white to overspin like a dragster's tyres.

Tribology is a fascinating subject and much misunderstood by virtually all snooker and pool coaches.

Take this example from the English Pool Association's head coach for instance.  Almost everything he expounds on this video clip is incorrect.

http://www.youtube.com/watch?v=I0bIkuZO_fc

and if you wanna learn more about legs running fast before going peeoooooooooow, the Arthur Jones gramophone record "My Training Regime in Aden" tells you all you need to know

Hi Poker, I think it was me who said it was semantics, a couple of things, i'm still not sure about, in your analysis.
First, this.

BurtSaddo. 19 Jan 10 20:24
ok do this

1 put green ball on green spot
2 place cue ball 2 or 3 foot away from green
3 make sure cue ball, green ball and corner bag are in a straight line
4 hit cue ball dead centre at good pace and go and fetch the green ball out of the bag
5 set up the above exactly the same
6 hit cue ball between centre and top using same power as previous shot
7 now fetch the green AND white out of the corner bag
8 if they are not there then you are no snooker player
billy hill 19 Jan 10 20:26
ps i have a degree in mechanical engineering so know about this stuff
Pokermonster 19 Jan 10 20:26
Good evening Burt. :)

The only way you will be fetching the cueball out of the pocket is if you hit it harder than the first shot.

And, secondly, was it ever answered why a professional player ever hits the ball on the top? (if not to apply the seemingly fictitious "topspin", of course.

Hi Pm.
Rolling, sliding, topspin, my head hurts, anyway.





[img]http://community.cdnbf.net/community.betfair.com/user/liamcol/1f7208328097d64bcef6b074ea5dc7af.jpg?v=267750[/img]

I haven't read the full thread so forgive me if this has been stated.

Putting topspin on a ball isn't to make it travel further, but to make it travel in the direction which you desire.

Yes, in the direction which you desire

The direction is mostly governed by one's aim, although spin does can have an effect after collision.  But not always, sir.

Yes the sliding ball will effectively create a stun shot.

Hitting the cue ball above centre will effectively make it roll on to the object ball and continue forward depending on the angle and speed you hit the shot.

That is correct AG.  I'm impressed, sir.  If you find the time to have a read through the thread you will see that quite a few started with a different opinion.