If the tip and cue ball only touch so briefly, why the difference in power?
- Thread starter arsenius
- Start date
The applied force rises, reaches a peak, then falls off to zero, then goes negative, etc. If you plot that against time, the cue's speed (momentum actually) at any moment is the area under the curve that has accumulated up to that moment. A sine function is a reasonable guess at the overall shape of the curve, and really is a pretty good approximation according to one set of accelerometer curves available.Patrick Johnson said:
The sine function takes angles as its argument. It starts off at a phase angle of zero, and is zero there. It reaches a peak at 90 degrees, then falls back to zero at 180 degrees. If impact occurs at 180 degrees, then the cue is coasting at the moment of impact, and the cue's momentum is the area under the entire positve "hump" of the curve.
Now imagine plotting the same curve but stretching it out over time so that every point of the curve (except at t=0) occurs later. It turns out that there will be more area under the curve at impact, and it will be at a maximum if impact takes place at a phase angle of 113.1449214817... degrees (if you must know). This corresponds to something like a 20-25% increase in speed (I'd have to re-calculate this). Hitting at this angle is unrealistic I think as it means a very, very long stroke, but an increase of 10-15% probably is not. (I believe I've seen something like this when practicing maximum draw by moving my grip hand back on the butt.) Here is a pictorial:
http://ww2.netnitco.net/users/gtech/Fsins.jpg
The time it takes for the tip to reach the cueball doesn't change very much for the three strokes shown. The same considerations apply to a more realistic curve shape, with harmonics mixed in, but the numbers are a little different. It remains to be seen though, just what happens in reality to the shape of the curve when extending it like this.
Jim
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After reading this thread which I find very interesting by the way, I was telling my buddy Vernon Elliott about the discussion and his response was that had he known playing pool was so complicated he would never been able to play it. Some of you who posted here know Vernon or at least know of him and he was known as having a monster stroke during his playing days. Vernon helped me some when I first started playing pool and his most adamant commandment is to never hit the cue ball more than 1/4" off center and to let your stroke and acquired spin from collision off the OB provide control of the cue ball. For the record this post is to add a little levity to your complex discusion and isn't meant to be critical of anyone.
arsenius said:
for the same acceleration
off center hit: angular velocity (spin) + forward velocity = dead on: forward velocity ; for simplicity
Conservation of momemtum implies that if the angular velocity increases the forward velocity decreases.
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Bob Jewett said:
So Bob, what is the layman's/player's benefit to using a hard tip versus a soft tip? Not including less mushrooming and more consistent shape.
What can a hard tip do that a can't do or vice versa? Or even why would you want to use a hard tip over a soft tip?
Thanks,
JoeyA
That's what we've been discussing. It doesn't appear to be true.
Why wouldn't it increase the forward speed as much proportionately? Logic would suggest speed and spin would increase proportionately. How is force applied later different from force applied earlier?
pj
chgo
It is possible to get a fair estimate of draw distance for some cue speed, offset, etc. However, it's unlikely to be as accurate as with centerball or follow since you're hitting more downwards on the cueball and this amplifies the error in some things that aren't easy to quantify.arsenius said:
It's useless to a player though unless he or she knows how to get the cue going at, say, 6.3 ft/sec. You could calibrate your arm I suppose, but I doubt that even the technical types have much of a stomach for that.
Jim
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I think a hard tip gives a more consistent hit. It also seems to be more efficient -- that is, the stick doesn't have to be moving as fast to get a given ball speed.JoeyA said:
There is a hand-waving argument that a hard tip should be able to get more spin on the cue ball, but this is countered by the observation that soft tips tend to hold chalk better.
Doug said:
Why in the world are you giving up Vernon "The Great" Elliott's secrets?
Are you able to cut the object ball in the closest right corner pocket?
Now tell Vernon, that's a secret JoeyA wants to know.
Although I never had the pleasure of meeting him or see him making any of his fantastic bank shots, his legendary prowess has traveled all the way to the bayous of Louisiana where he is more of a Legend than anyone would expect.
Semper Fi,
JoeyA
Patrick Johnson said:
Start here;
We know the farther from the center of the cue ball we hit, the more spin.
We know there is a finite amount of energy as we hit the CB.
If the spin increases, then that energy has to come from somewhere and the only other place is the energy expended to move the CB forward.
This is one reason we try to hit near the center of the CB on break shots. More energy is transformed into forward speed for a better break.
The hand-waving counter argument is that a softer tip stays on the ball longer, and because the ball is rotating during tip-to-ball contact, the tip moves around the side of the ball and gets farther off-center, resulting in a miscue towards the end of the hit.Deadon said:And with a softer tip I think you can safely cue farther from the center, which, I believe, geometrically increases the spin while the loss of speed from the soft tip is only linear............. I think
For those who believe in soft tips, we have the counterexample of Rafael Martinez who has his new tips taken down until there is no sidewall. He is nearly playing on ferrule. He spins the ball pretty well. It's not what I'd recommend, but it seems to work for him. And, he came back from the dead.
What you say is true, but that wasn't the argument as I read it. For a given tip offset, more energy into the ball means more speed and spin. Both go up at very nearly the same same rate, since its spin is very nearly proportional to its speed, for a given offset. Speed doesn't quite keep up with the spin (but almost does), because the faster spining ball increases the effective tip offset slightly more than a slower spinning ball.Deadon said:
Jim
Ron Shepard
I love the scientific talk especially when it gets to my level like this post.
While like some of you, I get lost in the physics discussions but if I hang around them long enough I will mine a couple of nuggets worth banking.
Bob Jewett, Jal, Pat Johnson, Mike Page and a couple of others.... These guys provide lots of good information that is USABLE. Don't let the techno talk send you into a tailspin. The only one we're missing from these discussions is Ron Shepard. Ron is like a monster typhoon in these discussions, adding laser like dialogue to them but at the same time, leaving a little corn for us mere mortal's sustenance. It's a shame that he doesn't join in her on AZ.
I've learned to listen better, especially when these people are involved. They have good ideas that can help you with your game. Stay the course.
JoeyA
Patrick Johnson said:
I love the scientific talk especially when it gets to my level like this post.
While like some of you, I get lost in the physics discussions but if I hang around them long enough I will mine a couple of nuggets worth banking.
Bob Jewett, Jal, Pat Johnson, Mike Page and a couple of others.... These guys provide lots of good information that is USABLE. Don't let the techno talk send you into a tailspin. The only one we're missing from these discussions is Ron Shepard. Ron is like a monster typhoon in these discussions, adding laser like dialogue to them but at the same time, leaving a little corn for us mere mortal's sustenance. It's a shame that he doesn't join in her on AZ.
I've learned to listen better, especially when these people are involved. They have good ideas that can help you with your game. Stay the course.
JoeyA
Andrew Manning said:
I think what he meant to say is that the energy you start with will equal to the total energy of the resulting reaction of both the cueball and the cue.
But going to the original question; the power of the shot is derived from the acceleration (final speed during contact / time elapsed from zero speed to contact) of the cue. Since we usually play with the same cue (except for breaking), acceleration is the factor that affects the power of the stroke either you want to move the ball forward, or you want to spin the ball.
I wonder why people wants to complicate it.
Oh, I see what you're saying. The "effective tip offset" is increased as the tip rotates more on the ball. That's how normal sidespin works. But how have you increased the range of effect by increasing the time it takes to reach maximum? You still can't push past the miscue limit or faster than your arm's limit.
Vernon's secrets
Actually Joey, what I "divulged" from Vernon is not something that he holds as a secret although he has volumn's of things that he still holds as privileged information. Regrettably there are many shots that Vernon could make, including the one you illustrated, that I can't make. But I don't get down on myself about it because accompanying me are many world champions that can't duplicate Vernon's shots. By the way, Vernon says the illustrated shot is not one he rated as "difficult" when he was playing. I am going to show him your post. He will get a kick out of seeing it.JoeyA said:Why in the world are you giving up Vernon "The Great" Elliott's secrets?
Are you able to cut the object ball in the closest right corner pocket?
Now tell Vernon, that's a secret JoeyA wants to know.
Although I never had the pleasure of meeting him or see him making any of his fantastic bank shots, his legendary prowess has traveled all the way to the bayous of Louisiana where he is more of a Legend than anyone would expect.
Semper Fi,
JoeyA
Doug said:
Tell Vernon, if he tells me the WHOLE SECRET to this shot that I will take the secret to this shot to my grave.
Actually, I am serious. I have moved the object ball toward my hole about 6 inches only once in hundreds of tries. FTR, I believe that I can make ANY shot that anyone else in the world can make. I just have to learn or teach myself how to make it. This is one of the few shots in the world that I have been stupid enough to believe that it an be made without ever having seen it being made. 
I have never seen this shot made and have only heard the folklore of this shot and others in which Vernon has been the central figure.
Best Regards to Vernon.
JoeyA
BTW, Doug do you know how to use www.cuetable.com ?
It would be GREAT and I know WEI the creator of cuetable would help if you were interested in building a catalog of Vernon's shots for posterity. That previous shot was depicted using www.cuetable.com and it is free, fun and after you get used to it, easy to use. It could be called the Vernon Elliott Collection and would be famous for generations to come.
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Jal said:
Hi Jim;
Perhaps, here's were we differ. Its my understanding, and I may well be wrong.
Spin increases several times per unit of force/energy while speed decreases purportionally with force/energy.
That factor enables us to spin the hell out of the CB and kill it as it hits a thin cut shot. What us old times use to call a soft stroke. Not hit hard, lots of cue speed and cue very low. Perhaps I don't explain well, but if you have seen Keith cut a ball backwards a few times and the CB moves about 6 inches after contact, it would become more understandable.
The result is actually,
with more energy-more offset-more spin-less speed
with same energy-more offset-more spin-less speed
the more the offset, the more spin and less speed
Of course, I may be wrong, but I haven't been drinking..........yet
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