Panhdlce said:Sometimes when I hit a draw shot the cueball stops dead then reverses direcrion, other times the instant it strikes the object ball it draws?
Andrew Manning said:The delay before the CB comes back depends on the speed of the cloth. On faster cloth, the spin will bring the CB back more gradually, due to the spin being converted (by friction) to translational speed more slowly (because there's less friction). On a slower cloth, the CB's spin will very quickly become translational speed due to the high friction, and will seem to come back with less delay.
It's worth noting that the CB starts coming backwards immediately in both cases, it just picks up speed more quickly in the one case than the other.
The other relevant factor is CB bounce. If you elevate, and the CB is actually slightly above the cloth when it hits the OB, then it will bounce upward and slightly forward after contact. In that case, the CB is actually still moving forward, and so there is a real delay before the spins starts moving it backward. This delay will be longer or shorter depending on cloth speed.
-Andrew
Panhdlce said:Sometimes when I hit a draw shot the cueball stops dead then reverses direcrionother times the instant it strikes the object ball it draws?
WesleyW said:You did not hit a draw shot, you hit center.
Here's a good super-slow-motion example:av84fun said:Andrew, I'm sticking my neck out here but I am almost certain that I have seen slow mo video showing that the cb can skid forward after impact...I think due to the power of forward momentum briefly overcoming the reverse spin.
I'm sure Bob or Dr_Dave will be able to confirm or deny that.
dr_dave said:Here's a good super-slow-motion example:
Here, the CB is slightly heavier than the OB ... that's why it moves forward slightly after impact, before drawing back.
Regards,
Dave
Regardless of the speed, if the CB and OB are the same weight and the CB hits the OB squarely, the CB will theoretically deliver all of its momentum to the OB, and the CB will momentarily stop in place before drawing back due to the bottom spin. I wrote "theoretically," because this assumes the balls are perfectly elastic (i.e., no energy loss during impact). In actuality, the CB does retain a very small portion of its forward speed in a non perfect collision (per the math and physics in TP A.5).av84fun said:Even if cb/ob are of identical weight, if the cb strikes the ob at 50mph (assuming for sake of argument that the balls could withstand that impact without shattering) then I would guess that the CB is going to move forward...even if it was spinning in reverse at a substantial rpm value.
dr_dave said:Regardless of the speed, if the CB and OB are the same weight and the CB hits the OB squarely, the CB will theoretically deliver all of its momentum to the OB, and the CB will momentarily stop in place before drawing back due to the bottom spin. I wrote "theoretically," because this assumes the balls are perfectly elastic (i.e., no energy loss during impact). In actuality, the CB does retain a very small portion of its forward speed in a non perfect collision (per the math and physics in TP A.5).
Now, at 50 mph, it would be very likely the CB would be slightly airborne when it hits the OB (due to hop caused by cue elevation). In that case, it will advance forward some because it is not hitting the OB squarely. For an exaggerated example, see the last shot in HSV B.6
Regards,
Dave
You're very welcome.av84fun said:THANKS! Your posts never fail to teach. Whether I learn anything is another matter altogether!!!
(-:
Jim
Learning to use squirt to your advantage, huh??dr_dave said:I aim to swerve.![]()
Dave
You bet. I don't like to throw games.pooltchr said:Learning to use squirt to your advantage, huh??![]()
Steve
av84fun said:Other than a break shot where the cb hits a mass 9x its own weight, how does a cb reverse direction when struck with center ball??
If it is skidding at OB contact, it will stop dead and stay there...and if the cb has finished skidding and begins its forward roll, I don't think it will either stop dead (except momentarily) or reverse direction.
If hit with true center, I don't think there is any reverse spin.
What am I missing?
Thanks,
Jim
Andrew Manning said:The delay before the CB comes back depends on the speed of the cloth. On faster cloth, the spin will bring the CB back more gradually, due to the spin being converted (by friction) to translational speed more slowly (because there's less friction). On a slower cloth, the CB's spin will very quickly become translational speed due to the high friction, and will seem to come back with less delay.
It's worth noting that the CB starts coming backwards immediately in both cases, it just picks up speed more quickly in the one case than the other.
[...] This delay will be longer or shorter depending on cloth speed.
-Andrew
Panhdlce said:Correct way to stroke a draw shot?
Sometimes when I hit a draw shot the cueball stops dead then reverses direcrion, other times the instant it strikes the object ball it draws?
av84fun said:Andrew, I'm sticking my neck out here but I am almost certain that I have seen slow mo video showing that the cb can skid forward after impact...I think due to the power of forward momentum briefly overcoming the reverse spin.
I'm sure Bob or Dr_Dave will be able to confirm or deny that.
Regards,
Jim
mikepage said:The ball-cloth sliding friction you're taking about is actually a separate property from the speed of the cloth.
New Simonis, for example, is like ice-- both fast and slick. It will have a longer delay for a straight-on draw shot and a longer sideways arc for an almost straight on draw shot.
Old Simonis that's stretched tightly can be just as fast, but it's not so slick. Imagine a steel surface painted with skid-resistant paint. It might be very fast (low rolling resistance) but it's also sticky (high sliding resistance).