- #1
noname12345
- 31
- 4
1) Can the contact between two pool balls impart any kind of spin, other that about its horizontal axis due friction contact with the table surface?
2) If a ball is in motion (traveling in a straight line) and contacts a cushion, can that contact impart spin to the ball such that when leaving the cushion, is path (when viewed from above) forms an arc?
Background: I love playing pool, but in lock-down I've taken to playing pool against my computer. I've found a version that isn't to annoying, but in addition to various simple bugs (like a ball managing to end up balanced on the frame of the table) is has this curious behavior that if you hit a ball hard such that it ricochets around that table without contacting any other balls or going in a pocket, after the second or third contact, it starts moving in an arc.
Including a couple of times when it skipped along a long cushion much like a stone skipped on a pond. Ie.Hitting a cushion, bouncing away and then moving in an arg to come back to the same cushion without hitting anything else. Two and even three times.
I am pretty sure I've never seen this IRL; and my instinct says that it is physically possible. I'm seeking to verify that instinct.
My thoughts on the two questions above:
1) When two smooth surfaced balls contact each other, the forces always act directly through the centers of mass, thus no spin can be imparted.
2) When a ball hits a cushion, any existing spin (about its vertical axis), will act to change the angle at which it leaves the cushion; and the contact will reduce the moment about that vertical axis -- friction lost to the cushion -- but no additional spin (about the vertical axis) will be imparted to the ball by the contact.
Thoughts?
2) If a ball is in motion (traveling in a straight line) and contacts a cushion, can that contact impart spin to the ball such that when leaving the cushion, is path (when viewed from above) forms an arc?
Background: I love playing pool, but in lock-down I've taken to playing pool against my computer. I've found a version that isn't to annoying, but in addition to various simple bugs (like a ball managing to end up balanced on the frame of the table) is has this curious behavior that if you hit a ball hard such that it ricochets around that table without contacting any other balls or going in a pocket, after the second or third contact, it starts moving in an arc.
Including a couple of times when it skipped along a long cushion much like a stone skipped on a pond. Ie.Hitting a cushion, bouncing away and then moving in an arg to come back to the same cushion without hitting anything else. Two and even three times.
I am pretty sure I've never seen this IRL; and my instinct says that it is physically possible. I'm seeking to verify that instinct.
My thoughts on the two questions above:
1) When two smooth surfaced balls contact each other, the forces always act directly through the centers of mass, thus no spin can be imparted.
2) When a ball hits a cushion, any existing spin (about its vertical axis), will act to change the angle at which it leaves the cushion; and the contact will reduce the moment about that vertical axis -- friction lost to the cushion -- but no additional spin (about the vertical axis) will be imparted to the ball by the contact.
Thoughts?
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