what is the process that allows a player to bounce the balls in?

[scottycoyote]

well its still going on lol. Went and played tonight......and even the guy i was playing commented on it......long straight in shots, expecially if they were just centerball or stop shots......theyd fly in the pocket. I made 2 or 3 in one game alone and he was like.........what!! no way that ball should have fell. Its like they all my stop shots have get in english on them.

 

[Cameron Smith]

Would it not depend also on the quality of the rails, the rubber that is?

At one of the places I play, the rails on this one table have not been changed as long as I can remember playing there. No ball will go in, if it does go into the heart of the pocket. Great table to practice your shot making as it has 4.5" pockets and plays smaller. Horrible to practice banks on though.

 

[scottycoyote]

well this is the same place ive been playing the last 6 years........same table we always gamble on, felts not new, no new bumpers.......the only thing different is im wearing a glove lol

 

[Andrew Manning]

Andrew,

It could be a lack of imagination on my part, but I don't see the mechanism you're describing in play. In a vacuum, the tennis ball should bounce up to the same height in both cases, with the caveat that the different friction should cause some differences in the arrangement of internal stresses, which might affect the coefficient of restitution.

Well, I'll admit that I don't really have a solid physics explanation for it (sad as that makes me), but I really don't think the tennis ball "skipping" off moist grass and not bouncing as much has anything to do with the surrounding air. I've experienced it myself, and it really seems that the damp grass lubricating the ball's impact with the ground truly decreases bounce. But again, I have to admit I can't back that up with physics without leaving big holes in the explanation.

But leaving the tennis court and going back to the pool table, swerve could indeed have everything to do with a ball glancing off the rail with reverse vs. running english. I know for me, if I'm playing a ball frozen to the rail, I can make it "hug" the rail with more ease playing with inside english on the CB (which would transfer some amount of reverse english to the OB). Of course that may be because I'm aligning slightly rail-first and the inside directs the CB off the rail into the OB better, but I think the OB spin has something to do with the "hugging the rail".

And scottycoyote, I'm starting to think what you're experiencing is the power of positive thinking. Every factor I know of that can make a ball more likely to go in after contacting the rail is something you claim is the same as before when they weren't going in. I say, don't question it too much, just keep shooting confidently, and I imagine you'll keep seeing things go your way.

-Andrew

 

[mikepage]

Try this shot, with just the CB, at the speed you're talking about. Try to hit the same point on the long rail before the pocket, with both right and left english. [...]

I tried it on my table. I measure no difference in the bank angle with inside or outside english. I realize this could depend on the rail cloth though.

[...] The other is that the ball seems to "skim" the rail more lightly with reverse English at a shallow angle like this. The running english (left in this case) almost seems to make it grab the rail and throw itself away, whereas the reverse english seems to make it brush the rail and not kick away from the rail nearly as much.

I have a few comments. First I suspect you actually have check (reverse) spin on both shots. The reason I say this is that when putting topspin on a cueball it's hard to achieve greater than natural roll topspin. By the same token, it should be hard to achieve greater than natural running english when hitting with outside sidespin at a very shallow angle. If this is the case, then unless we use drag draw to increase the spin/speed ratio, most of our shots will have a check (i.e.., slow down parallel to the rail) interaction with the rail whatever english we use.

Second unless there's something subtle going on, the parallel-to-the-rail and the perpendicular-to-the-rail motions should be independent of one another. The friction force, whatever its sign and magnitude, is directed parallel to the rail and affects only the motion parallel to the rail.

It may *look* like some shots bounce more off the rail than others, but I think what is really happening is it's coming off the rail the same way but because you slow it down parallel to the rail the angle it comes off the rail will be steeper.

If I am right that the rubbing for both the right and left english cases is in the "slow down" direction, then provided the coefficient of friction is independent of the rubbing speed, the angle off the first rail should be the same. (which is what I observe).

The situation changes going into a rail at a steeper angle (say at a 45 degree angle) because now the running english is really running english, i.e., it acts in the speed-up direction.


mike page
fargo

 

[steev]

Y'all are making me laugh at work. I went through this theory a couple of months ago, so here's my $.02. "Get-in" english is for real, and you can see numerous pro's, etc. using it if you watch. Usually if they're sending a ball down a rail, you'll see them hit it with inside english to transfer a little spin on the OB. I played with this for a while, and, well, versus centerball (throw spin only), it's not a huge difference. Versus opposite spin, it is in fact a huge difference.

I'm not going to comment on y'all's scientific discussion on friction and whatnot, as I don't feel the need to validate my position. It works and I know it, if you disagree, oh well.

-s

 

[Andrew Manning]

Y'all are making me laugh at work. I went through this theory a couple of months ago, so here's my $.02. "Get-in" english is for real, and you can see numerous pro's, etc. using it if you watch. Usually if they're sending a ball down a rail, you'll see them hit it with inside english to transfer a little spin on the OB. I played with this for a while, and, well, versus centerball (throw spin only), it's not a huge difference. Versus opposite spin, it is in fact a huge difference.

I'm not going to comment on y'all's scientific discussion on friction and whatnot, as I don't feel the need to validate my position. It works and I know it, if you disagree, oh well.

-s

Despite you not feeling the need for validation, I agree. I only started trying to come up with physics to support it because I observed it experimentally on a pool table first.

Mike, you have a point that at a shallow enough angle, it's hard or maybe impossible to achieve "greater-than-rolling" running english along a rail. I'm giving up on coming up with physics-based explanations, since I haven't found one yet that really holds water. I still think get-in english decreases how far the CB bounces out from the rail, though.

-Andrew

 

[Jal]

Well, I'll admit that I don't really have a solid physics explanation for it (sad as that makes me), but I really don't think the tennis ball "skipping" off moist grass and not bouncing as much has anything to do with the surrounding air. I've experienced it myself, and it really seems that the damp grass lubricating the ball's impact with the ground truly decreases bounce. But again, I have to admit I can't back that up with physics without leaving big holes in the explanation.

I think we both agree that on dry clay the ball bounces at a steeper angle than on wet grass. There's no question about that since it's slowed down more by the clay in the direction parallel to the ground. But this shouldn't affect the other component of its motion in the vertical direction. It won't reach the same height off of the grass because, at the shallower angle, it has to pass through more air to get there and drag takes its toll. A tennis ball is sort of flimsy so maybe differences in internal stresses between the two situations also have some marked effect (but which way?).

But leaving the tennis court and going back to the pool table, swerve could indeed have everything to do with a ball glancing off the rail with reverse vs. running english. I know for me, if I'm playing a ball frozen to the rail, I can make it "hug" the rail with more ease playing with inside english on the CB (which would transfer some amount of reverse english to the OB). Of course that may be because I'm aligning slightly rail-first and the inside directs the CB off the rail into the OB better, but I think the OB spin has something to do with the "hugging the rail".

Since the OB is struck at or very near its equator, it really can't swerve anything like the CB. It can curve a little though from three obscure effects, but at least two of them have been calculated to be very small and probably don't help it hug the rail in any significant way. The third one is also likely very small since OB curve is, I think, very hard to detect unless it has an unusually high spin/speed ratio.

It seems more likely to me that the inside english is providing some aim correction, and/or less throw depending on how much draw or follow is present.

Not trying to be contrary, Andrew. Just reporting what I know, or think I know at any rate. Could be wrong.

Jim

 

[thoffen]

Most of it can be explained as that you are banking the ball in. If you bank the ball in, it's coming in off a better angle to catch the pocket facing and fall in, making the pocket bigger. If you overcut it, you've got less room. If you hit the same ball into the near point, then you hit it much more accurately, but it still won't go in.