I'm happy for nobody to agree with me at this point, abito; I expected as much to be fair.

All the more satisfying when they do finally agree, though, eh?

There is a simple test that proves this point:

Start with the cueball on the brown spot and the blue on its own spot. These are the only two balls on the table.

First shot: Send the white into the blue at an (almost) full on collision, sending the colour up over the pink and black spots and back to baulk, coming to rest within two inches the baulk cushion. If the blue bounces back into the white, start again. This first shot should be played plain ball. Note where the white finishes.

Second shot: Replace the balls and try again using as much topspin as you can muster. You can even move it closer to the blue if you like. Keep trying until the blue finishes in the same place as before; this is your proof that you have not inadvertantly struck the white harder. Note where the white finishes. It will be in the same place as with the first plainly struck shot.

who fhucking cares anyway, I know who killed Archie Mitchell so stick that in ya pipe

as bad a fishing thread as the 'which course is uphill all the way round' one imo

Of course top spin works. As cue ball hits object ball it grips cloth and (effectively) shoots forwards. Hence top and side to break into reds (via potting black and use of the cushion works)

There is a difference between rolling, slipping, and sliding.

Rolling is when the point of contact of the ball with the table is stationary in the frame of the table.

Sliding is when the contact point moves in the same direction as the centre of mass, i.e. the rotation is less than required for rolling.

Slipping is when it moves in the opposite direction to the centre of mass, i.e. the rotation is more than required for rolling.

Friction between the contact point and the table will act to**the motion of the contact point until the rolling condition is achieved.

When topspin is imparted to the ball, for example by striking the ball above its centre of mass, it will slip initially and may still be slipping when it collides with another ball.

**ard, I've already told him that, he's fishing.

I can assure you that I am not fishing Dr Crippen. Ask any of the regulars on here and they will tell you such behaviour is not normally my style.

What is more, I am certain everything I have written is one hundred percent correct.

Hi Poker :)
Yeah I will do - I've never done that before I must admit

i would normally have argued the point, but i wouldnt dream of second guessing PM when it came to a snooker question as he will clearly be correct :D

The stop shot, by the way, is not governed so much by where you hit the white, as how hard you hit it.

It must be sliding at the moment it collides with the object ball (full on) to achieve a perfect stop shot. Equally weighted objects react in this manner when sliding (see the curling stone example earlier).

Yes, you can achieve a stop shot using backspin, but this is only because you are skilled at judging when the cueball is in its sliding transitionary phase between backspinning and natural forward roll. It is far easier to execute a stop shot by hitting the white with more force, thus ensuring it is sliding for longer. Pros do this all the time, usually subconciously.

Good evening Shaky. :)

I hoped this would encourage a lively debate. And it has.

It does seem so unlikely at first I must admit. When discussing with friends around a snooker table, however, it is quite a simple matter to prove the point beyond doubt. Much more difficult to convince the sceptical on a forum of course!

The geometry is thus:
7/10 of the diameter up the cue ball from table bed is the sweet spot. an impact here with a cue tip causes the ball to roll forward at the pace you hit it. At 5/10 diameter (centre striking , pure stun) it will slip forwards with no spin. More than 7/10 diameter up it will rotate faster than it rolls, continue after impact due to imparted topspin. Below 5/10diamter striking it will rotate slower than it rolls and will screw back after impact.

The drag shot is often used to when a player wishes to strike the ball firmly (possibly to counteract an uneven table) yet wishes the ball to travel relatively slowly.

It is executed in much the same manner as a backspin, or draw, stroke. The difference being any backspin will have worn off before cueball meets object ball.

There are three recognisable physical areas to the drag stroke. The cueball has been struck below its centre of mass and therefore begins travelling in the direction of the stroke whilst also spinning backwards.

When this backspin wears off the white begins to slide momentarily (my research with high speed video suggests this phase tends to be roughly one tenth of the distance travelled during the backspinning, but I cannot offer you proof such a ratio is constant at this stage). If the white collides full on with the object ball during this stage it will stop dead.

The third stage of the drag shot is where the white finally regains its grip and begins to roll forward naturally.

The drag shot is particularly useful when you wish to retain as much sidespin as possible over a long distance, as equatorial spin is diminished far slower than backspin. The drag shot has nothing whatsoever to do with dressing up like Prescilla, Queen of the Desert.

Dr Crippen 19 Jan 19:36

Put backspin on a ball and when it hits the cushion it comes of the cushion faster. Correct.

Put top spin on the ball and the spin has the opposite effect. Incorrect. This is just its natural forward roll and momentum.

interesting comments on drag shot - pm, thanks (i know what it is but wanted to see how you described it..!)

As much as i respect your opinion, i can't help but think you are wrong and would show you myself if i could! Intrigued as to your reasoning though, so will continue reading with interest. Cheers.

You're welcome Reyes. Thank you for your interest sir.

Where's Schalke04 when you need him? He'd put us all right.

Hi Reyes. :)

The chap who posted up that clip is well-meaning, but I am afraid to say he is rather a poor player.

Whilst he is indeed striking above centre in potting the yellow, the cueball is hit so hard it has little option but to bounce back slightly after colliding with the object ball. It does this because with are witnessing this example on an English pool table where the white is an eighth of an inch smaller and nearly an ounce lighter than the colours.

What we see then is its substantial forward momentum creating backspin. I know this might appear contradictory in writing, but that is what is happening.

At no time does the cueball display extra rotation (spin) in the same direction it is travelling. There is never any topspin in other words.

the only way to prove pm wrong is a video of a cueball with spots coming off the cue. PM is right, once the balls collide backsi=pin is imparted, not topspin

Thanks for your support Evski. :)

Reyes: It only shoots forward, sir, after it has reversed back towards the player slightly, an effect caused because the white is significantly lighter than the yellow.