# Test Your POOL KNOWLEDGE … Take New Pool QUIZZES

#### Ratamon

##### AzB Silver Member
Silver Member
Annoyingly got 96 in physics. Can someone explain these two I got wrong please?

I always thought outside spin keeps the OB more true to the line and that any sidespin increases squirt and therefore sends the CB wider than the tangent line (until the swerve takes effect and brings it closer to it). Where am I wrong?

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Annoyingly got 96 in physics. Can someone explain these two I got wrong please?

I always thought outside spin keeps the OB more true to the line and that any spin increases squirt and therefore sends the CB wider than the tangent line (until the swerve takes effect and brings it closer to it). Where am I wrong?

FYI, I will be doing a set of follow-up videos showing at the table the answers to each pool physics quiz question. But for now, answer explanations for the questions you missed can be found here:

- Concerning inside spin reducing throw, see the answer to the "Why does IE increase throw at small cut angles and decrease throw at larger cut angles?" question on the inside spin resource page.

- Concerning narrowing the carom angle with inside follow, see the answer to the "Is inside english a better choice than outside english to limit CB sideways drift on some shots?" question on the inside spin resource page.

Enjoy,
Dave

#### Ratamon

##### AzB Silver Member
Silver Member
FYI, I will be doing a set of follow-up videos showing at the table the answers to each pool physics quiz question. But for now, answer explanations for the questions you missed can be found here:

- Concerning inside spin reducing throw, see the answer to the "Why does IE increase throw at small cut angles and decrease throw at larger cut angles?" question on the inside spin resource page.

- Concerning narrowing the carom angle with inside follow, see the answer to the "Is inside english a better choice than outside english to limit CB sideways drift on some shots?" question on the inside spin resource page.

Enjoy,
Dave

Thanks so much for doing this Dr. Dave! Appreciate the effort that went into pulling these quizzes together.

I’ve learned something new today. Will now look up the links you kindly shared

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Thanks so much for doing this Dr. Dave! Appreciate the effort that went into pulling these quizzes together.

You're welcome. The quizzes were fun to put together, and I am glad people are enjoying them. So far, the quizzes have already been taken more than 400 times!

I’ve learned something new today. Will now look up the links you kindly shared

I'm glad to hear it. I hope the links help. Please let me know if they don't.

#### buckshotshoey

##### AzB Silver Member
Silver Member
Not bad. Some shots were very difficult to see.

#### Patrick Johnson

##### Fish of the Day
Silver Member
- Concerning narrowing the carom angle with inside follow, see the answer to the "Is inside english a better choice than outside english to limit CB sideways drift on some shots?" question on the inside spin resource page.

The reasons why this works are:
• the CB swerves into the OB causing the CB angle to straighten slightly (and more with more cue elevation).
• the added surface contact speed at impact reduces friction between the balls (see throw speed effects), which:
• creates less throw, allowing for a slightly fuller hit.
• results in less topspin loss, allowing the CB to follow more.
In your "curve the OB" demonstration (another thread) you said that topspin combined with a little cut angle creates a "masse hit" on the OB - does that happen here too with follow and inside spin, putting a little masse spin on the CB after contact?

pj
chgo

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#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Not bad. Some shots were very difficult to see.

That's a great score, especially compared to the average. FYI, in the PDF answer key, we identify many of the calls as "TOUGH CALL" (partly due to the difficulty of seeing everything you need to see in video), and I usually give Mulligans for those when I administer the quiz in person (e.g., during instructor training).

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
In your "curve the OB" demonstration (another thread) you said that topspin combined with a little cut angle creates a "masse hit" on the OB - does that happen here too with follow and inside spin?

A noticeable amount of OB swerve is possible only with a chalk mark at the CB-OB contact point. The inside follow effects are much, much greater under normal conditions.

#### Patrick Johnson

##### Fish of the Day
Silver Member
A noticeable amount of OB swerve is possible only with a chalk mark at the CB-OB contact point. The inside follow effects are much, much greater under normal conditions.
Sorry, I meant to ask about masse spin on the CB (I changed my post just now to clarify that).

pj
chgo

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
topspin combined with a little cut angle creates a "masse hit" on the OB - does that happen here too with follow and inside spin, putting a little masse spin on the CB after contact?

I already addressed the OB. Concerning the CB, from the top item on my list that you quoted: "the CB swerves into the OB causing the CB angle to straighten slightly."

Although, the masse swerve happens before OB contact (unless the CB is really close to the OB, in which case some after-collision CB swerve is possible).

#### Patrick Johnson

##### Fish of the Day
Silver Member
I already addressed the OB. Concerning the CB, from the top item on my list that you quoted: "the CB swerves into the OB causing the CB angle to straighten slightly."

Although, the masse swerve happens before OB contact (unless the CB is really close to the OB, in which case some after-collision CB swerve is possible).

Sorry, I'm not communicating clearly today. I'm wondering if there might be a meaningful amount of after contact CB swerve because of the CB's tilted spin axis (side + follow). I suppose if inside spin could tighten the carom angle this way then outside spin could widen it... but I'm guessing a very small amount if any.

pj
chgo

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Sorry, I'm not communicating clearly today. I'm wondering if there might be a meaningful amount of after contact CB swerve because of the CB's tilted spin axis (side + follow). I suppose if inside spin could tighten the carom angle this way then outside spin could widen it... but I'm guessing a very small amount if any.

The after-collision swerve is due to the topspin alone, but this is the normal follow action. The inside spin (which can be thought of as totally independent) has no effect on the follow action. Check out this video that shows how top/bottom and sidespin are independent:

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
FYI, I will be doing a set of follow-up videos showing at the table the answers to each pool physics quiz question. ...

FYI, here's the first installment of the Pool Physics Quiz Answer Demonstrations (Q 1-10):

Enjoy!

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#### dr_dave

##### Instructional Author
Gold Member
Silver Member
FYI, here's the first installment of the Pool Physics Quiz Answer Demonstrations:

Enjoy!

Please give me some feedback on this video. If people don't like it, I might scale back my efforts on the additional videos I have planned to demonstrate answers to the remaining questions in the Pool Physics quiz. I might decide to cover only the remaining questions that are the most interesting or give people the most trouble (instead of all of them). Also, I would like suggestions or feedback concerning the format so I can improve things in the remaining videos.

Thank you!

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#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Please give me some feedback on this video. If people don't like it, I might scale back my efforts on the additional videos I have planned to demonstrate answers to the remaining questions in the Pool Physics quiz. I might decide to cover only the remaining questions that are the most interesting or give people the most trouble (instead of all of them). Also, I would like suggestions or feedback concerning the format so I can improve things in the remaining videos.

Thank you!

I plan to start Part 2 later today; so if anybody has any input or suggestions, please let me know soon.

Thanks!

#### justnum

##### Redhawk PI
Silver Member
Exciting videos and you have a great library of older videos.

A lot of new social media is transitioning to shorter form content.

Its common for long videos to be edited down into smaller more digestable chunks.

I am not saying change anything. I am saying add the option for viewers to see smaller amounts of content.

And in terms of the physics is there any way for younger fans to explore physics concepts, put some brain teasers to get people thinking.

The content does get dry when its all facts after facts.

Please take the feedback in good health.

#### dr_dave

##### Instructional Author
Gold Member
Silver Member
Exciting videos and you have a great library of older videos.

Thank you.

A lot of new social media is transitioning to shorter form content.

Its common for long videos to be edited down into smaller more digestable chunks.

I am not saying change anything. I am saying add the option for viewers to see smaller amounts of content.

Excellent point. I will keep this in mind when planning future videos. On the other hand, I see my videos as complete and detailed informational resources. I am not creating content simply for one-time and short-time viewing pleasure on social media. Regardless, your point is well taken. I might have a bigger impact and reach more people if I keep things shorter and simpler.

And in terms of the physics is there any way for younger fans to explore physics concepts, put some brain teasers to get people thinking.

I think this video is a good pool physics teaser:

The content does get dry when its all facts after facts.

Agreed.

Please take the feedback in good health.

I did. Thank you for your for the feedback and input. I appreciate it.

Any suggested format changes for the remaining parts of my Pool Physics Quiz Answers video series? Do you or others like the idea of presenting only the answers that are interesting or challenging from the remaining questions (instead of doing them all)?

Thank again,
Dave

#### couldnthinkof01

##### AzB Silver Member
Silver Member
I've bombed the physics.

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#### dr_dave

##### Instructional Author
Gold Member
Silver Member
I've bombed the physics.

Your score is still a little above average. Apparently, average pool players don't know pool physics principles as well as they think they might.

Nice job on the Pool Terminology Quiz! You killed the average on that one!

#### Fatboy

##### AzB Silver Member
Silver Member
I haven’t taken it yet.

trip home from Europe and the root canal are my excuses that I’ll stand by!

I’ll do the first one tonight. I have the tab open so I haven’t forgot. Bet the over