View Full Version : pool physics thing explanation please ?

05-14-2002, 10:33 AM
why does spin from cueball to object ball get transfered so much more with cueball draw then follow or english ? doesnt seem to transfer anything with cueball follow

05-14-2002, 10:48 AM
This has a lot to do with the amount of top spin (follow) and speed than you might think. The follow on the cue ball has to be spinning faster that the normal end over end natural spin of a cue ball rolling down the table.

If you use a striped ball for both the Cue ball and the object ball, for this explanation it might let you see the feedback that you are questioning.

You have to stroke the cue ball with above center hit. Enough to be able to maintain the english to hit the object ball with this follow action. The object ball will at the very minimum, Scoot.. a short distance, maybe just an inch or two.

When using bottom english, the cue ball has an easier time scooting across the table cloth, than with top english. Bottom english (draw) is easily the more often used english than top.. both draw and follow are mostley cue ball related than object ball. You are trying to make the cue ball to do something other than the natrual results of a normal center hit.

Transfer of the top english (follow) is actually making the object ball only scoot for a fraction of distance. Where as the draw shot will make the OB spin end over end, which makes it roll faster than normal after the hit.

Hope this helps.

Jay M
05-14-2002, 10:56 AM

I tend to disagree with this one. Draw is MUCH more difficult to control than follow and as such is used only when it's absolutely necessary to get the leave. I would rather follow 3 rails around the table than to try to draw 3 feet into a line.

Jay M

05-14-2002, 11:18 AM
Draw is a great tool to have and use when necessary. I use it a lot also.

The observation that I was making was that Draw was just used more than follow.

Ralph S.
05-14-2002, 12:39 PM
I agree about draw being much harder to control. I generally follow or use center ball hit for the majority of my position play.
Ralph S.

05-14-2002, 01:06 PM
I dont understand this.
When i put two object balls in line an inch seperated and shoot the first objectball straight in the second with a litle follow on the cueball from an angle so the cueball doesnt interfere, the first object ball goes forward after pocketing the second ?? how can follow on the cueball put follow on the object ball?
This is just weird.
Things get even more weird with long ball clusters .
I tought when you hit a straight 10 ball cluster only the last one would move but instead they all move the first fastest and the others slower and slower ...
There are so many other things like this ...
any logic in this ? where can i read about this ?

05-14-2002, 01:15 PM
First of all, 'draw' on the cue ball will only put 'follow' on the object ball. Its like gears and the rotation of one gear to another.. they can never be the same rotation.. only opposite.
Draw puts follow on the ob (remember, you have to hit the cue ball with draw and enough speed that when the cue ball strikes the object ball, there is still 'draw' on the cue ball)

Follow will make the ob slightly spin in the reverse and only momentarily.

In the cluster shot, all balls have to be lined up in a straight line and touching each other for just the last ball to be moved.

You can do this by lining up 6 balls on the end rail and just rolling one ball into the last ball in the line.. Only one ball will leave the balls are lined up.. If any of the six balls are out of line (away from the rail) and are not touching (frozen to the balls on either side) this will not work..

05-14-2002, 02:05 PM
i know draw on cueball puts follow on object ball and follow on cueball should put draw on object ball but then how do you explain that when hitting an object ball with follow ( put draw on it ) it goes forward after hitting a second object ball ( 1mm away so the cloth friction doesnt do anything ).
and about the long ball cluster, i put them on the rail and like i expected the first two went in the pocket and the others moved slowly they didnt stop ...
i think this is because the power is transfered to all balls simultaniously ...
but when i put them all in a row 1 mm seperated they all still go forward a litle

so for that i now have one explanation and that is that the bounce of the balls isnt 100% ... this would explain the first problem too

any one has a pool table around and a friend to observe?
you should try playing a straight in shot with draw as hard as you can.
if the bounce isnt 100 percent your friend should see the cueball go a litle forward after hitting the object ball before accellerating back.
this is probably very litle since the speed it goes forwards only results in about 5 inches roll if tried with an object ball.

05-14-2002, 02:28 PM
I believe that any 'draw' imparted to an object ball from the cue ball is incredibly momentary. It is quickly overcome by the friction of the cloth, and becomes follow.

Also, don't forget the simple inertia factor of a ball. If the first ball in a straight combination hits the second ball in the combo, it will want to move forward (Newton's "an object in motion, tends to stay in motion"--if I have that correct).

05-14-2002, 02:41 PM
When object balls run into each other a lot of the spin disipates. You won't get as much draw as you had follow on the cue-ball. Like wise you won't have as much left-english on the object ball as you had right-english on the cue-ball.

There is a good article on http://www.tableskills.com about this effect and I remember seeing a diagram too.


05-14-2002, 04:29 PM
The Science of Pocket Billiards by Jack Koehler.

05-14-2002, 04:46 PM

First-off i'll assume that you are talking about tranferred side spin?
Very little spin gets transferred to an object ball no matter where it is struck. But in general, there would be no difference to the amount of transferred side spin if the ball is struck with follow or draw. It may be possible to transfer the most amount of spin with a stun shot. A stun shot (cueball sliding) will produce the greatest throw effect from a spinning cueball. The reason is due to the greater surface sliding speed when the ball is rolling or spinning backwards. This extra surface speed reduces the sliding friction somewhat, hence a little bit less throw.

It is difficult to demonstrate that follow or draw can produce the same transfer effect with a bank shot. This is because the follow or draw can change the angle of the ball off the rail (by causing the object ball to acquire natural roll or not) without any sidespin.

Make sure that there is sufficient distance between the object ball and rail (so that natural roll is achieved) and that you use a similar speed (note: similar speed at the moment of collision,not similar cue speed, test this by checking the rolling distance of the OBJECT ball).

To really be sure of what you are doing, use a striped ball as an object ball so that you can see where you actually struck it. It is likely that you are not striking the ball as far off center with follow as you are with draw.