..picks up reverse spin?

sikorsky · Jun 23, 2019

this terms' demonstrated by a cross side bank (two or three rails).
the object ball is an inch from the long rail. CB hits it firm on the right side at 5-10 degrees. The OB has right spin.. how does does it 'pick up left spin witnessed at the opposite rail'?

so far I got these replys:
- it gets the reverse spin in the air
- ..from the angle
- ..from the speed

but how?

Guess I'll have to go to a physics teacher and get an explanation of a super ball..

RiverCity · Jun 23, 2019

sikorsky said:
this terms' demonstrated by a cross side bank (two or three rails).
the object ball is an inch from the long rail. CB hits it firm on the right side at 5-10 degrees. The OB has right spin.. how does does it 'pick up left spin witnessed at the opposite rail'?

so far I got these replys:
- it gets the reverse spin in the air
- ..from the angle
- ..from the speed

but how?

Guess I'll have to go to a physics teacher and get an explanation of a super ball..

https://billiards.colostate.edu/normal-video/nv-b-22/

Patrick Johnson · Jun 23, 2019

It’s a series of spin events:

1. The CB colliding with the OB puts some “holdup” spin on the OB, which shortens the angle off the first rail.
2. The OB colliding with the first rail at an angle reverses the spin that was put on by the CB (just like any ball picks up “running” spin when it hits the rail).
3. The reversed spin throws the OB toward the side pocket off the second rail.

pj
chgo

Nostroke · Jun 23, 2019

It gets running english/spin naturally from the first rail. Running spin IS reverse spin when it hits the opposite parallel rail. Just do the circly thing with your fingers and you'll get it.

ChrisinNC · Jun 23, 2019

Patrick Johnson said:
It’s a series of spin events:

1. The CB colliding with the OB puts some “holdup” spin on the OB, which shortens the angle off the first rail.
2. The OB colliding with the first rail at an angle reverses the spin that was put on by the CB (just like any ball picks up “running” spin when it hits the rail).
3. The reversed spin throws the OB toward the side pocket off the second rail.

pj
chgo

View attachment 523179

This is one of my favorite demo shots that I show a group of high school senior AP physics students that come here every year. Even the teacher has a hard time making sense of this shot! Another good one is showing how much the lead ball of two frozen balls can be thrown when hit on the correct side of the first ball, but it doesn't work at all if 3 or more balls are frozen in the same straight line.

dr_dave · Jun 23, 2019

sikorsky said:
this terms' demonstrated by a cross side bank (two or three rails).
the object ball is an inch from the long rail. CB hits it firm on the right side at 5-10 degrees. The OB has right spin.. how does does it 'pick up left spin witnessed at the opposite rail'?

so far I got these replys:
- it gets the reverse spin in the air
- ..from the angle
- ..from the speed

but how?

Guess I'll have to go to a physics teacher and get an explanation of a super ball..

FYI, this topic is covered in detail here:

two-times-across and three-times-across bank shots

Regards,
Dave

Tennesseejoe · Jun 23, 2019

It would be much easier to understand if clockwise and counterclockwise was used to describe ball rotation.

dr_dave · Jun 23, 2019

Tennesseejoe said:
It would be much easier to understand if clockwise and counterclockwise was used to describe ball rotation.

I agree. I can't redo the video, but "right" is the same as "CCW" and "left" is the same as "CW."

Regards,
Dave

joelpope · Jun 23, 2019

Tennesseejoe said:
It would be much easier to understand if clockwise and counterclockwise was used to describe ball rotation.

not really, if you are standing at the head rail and hit towards the foot rail with "clockwise" to the left long rail then it is running english but if you hit "clockwise" to the right long rail it is hold up english

Nostroke · Jun 24, 2019

joelpope said:
not really, if you are standing at the head rail and hit towards the foot rail with "clockwise" to the left long rail then it is running english but if you hit "clockwise" to the right long rail it is hold up english

I think your clocks run the opposite of mine.

Patrick Johnson · Jun 24, 2019

joelpope said:
not really, if you are standing at the head rail and hit towards the foot rail with "clockwise" to the left long rail then it is running english but if you hit "clockwise" to the right long rail it is hold up english

Yet in both cases you know which direction "clockwise" means...

pj
chgo

..picks up reverse spin?

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