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sensual7
02-06-2005, 06:07 AM
I'm no expert in billiards but i enjoy playing!

I once heard someone mentioning the 90 degree law ?!

meaning that i understood that the cue ball will deflect

from the object ball at exactly 90 degree angle?

i must have understood wrong because i see the cue ball deflect at all sorts of angles even using the normal
(standard) shot i.e. no english , no follow, no draw !!

what is this 90 deg law? and when does it apply ?

sensual7 /ccboard/images/graemlins/tongue.gif

ChuckR
02-06-2005, 06:12 AM
There are many posts and much discussion about the cue ball and angle deflection after contact. Go back and look at these on this site. There is more than you will ever need to know. CHuck /ccboard/images/graemlins/smirk.gif

Paul_Mon
02-06-2005, 06:18 AM
There's a good chance (about 95%) that you'll find this info doing a search here or at RSB or AZ or you can start your own thread.

Paul Mon~~~~learned 95% of everything I know doing searches

cheesemouse
02-06-2005, 07:57 AM
sensual7,

Welcome to the board. No one is blowing you off with your question. It is just the 'regulars' here have seen some of these recurring threads many times. There is an archieves search function in this forum that is most usful to the new comers. But in responce to your question about the 90 degree rule: the balls don't lie, if hit properly the c/ball will exit on that line when properly hit. Properly hitting the cueball is what it's all about...have a good time on the site...

DavidMorris
02-06-2005, 08:22 AM
Like the others have said, the 90-degree rule is one of those basic tenents of billiards. I suggest some formal instruction if you're serious about building a game, or at least invest in some good books and videos.

In a nutshell, yes the cueball WILL always depart from the object ball at a 90-degree tangent line when the cueball is sliding upon contact. For longer shots with softer strokes, a centerball hit will develop natural forward roll and therefore bend the tangent line forward to less than 90 degrees. Likewise, any reverse spin will cause the cueball to bend backwards at greater than 90-degrees from the tangent line.

So hitting centerball is not by itself a guarantee of a 90-degree tangent line result. The cueball must be sliding (a stun shot) upon contact. That's why you must alter spin and stroke speed to achieve the same results over greater distances and for different speed cloths. English (left or right spin) have no bearing on the tangent line from an object ball.

LARRY_BOY
02-06-2005, 11:10 AM
Buy Dr. Daves video and you will see and hear your questions answered. I watched it last night for the first time and it was very good.... both the 30 degree and 90 degree rule are coverd.

dr_dave
02-06-2005, 12:33 PM
<blockquote><font class="small">Quote sensual7:</font><hr>I once heard someone mentioning the 90 degree law ?!
meaning that i understood that the cue ball will deflect
from the object ball at exactly 90 degree angle?

i must have understood wrong because i see the cue ball deflect at all sorts of angles even using the normal
(standard) shot i.e. no english , no follow, no draw !!

what is this 90 deg law? and when does it apply ?<hr /></blockquote>
I have 9 online instructional articles (http://www.engr.colostate.edu/~dga/pool/bd_articles/index.html) dealing with the 90 and 30 degree rules. I think they answer your question well, with lots of good illustrations, examples, and online video demonstrations.

Also, there have been several recent CCB discussion threads that have covered these topics in great detail. To find them, see my convenient list of links to interesting threads (http://www.engr.colostate.edu/~dga/pool/threads.html).

sensual7
02-06-2005, 07:56 PM
thanks for not blowing me off! /ccboard/images/graemlins/frown.gif

i do participate in numerous forums of different types.

when you are a new member it takes time to adjust to a new forum, besides i'm not fluent in english.
i only just discovered how to use the archives.

anyway even if the threads are similar to other threads of 2years ago or 1month ago , a newcomer may well not know that.
anyway i got some very interesting replies from other members.
i really want to build my game !

regards
sensual7

sensual7
02-06-2005, 08:00 PM
thanks a lot!
i found your info very useful indeed !
i didn't know there were already plenty discussions regarding this issue.

i want to learn more because i am always mind-boggled by the fact that my cue ball always takes a different direction thanh the one i planned ,
yet at the same time i see the experts ( immonen, reyes, strickland, hohmann etc just taking a quick glance and already calculted the angle of deflection )

tahnks again !!

sensual7 /ccboard/images/graemlins/wink.gif

dr_dave
02-06-2005, 08:52 PM
<blockquote><font class="small">Quote sensual7:</font><hr> thanks a lot!
i found your info very useful indeed !
i didn't know there were already plenty discussions regarding this issue.<hr /></blockquote>
Welcome to the forum. I'm glad you found my stuff useful.

<blockquote><font class="small">Quote sensual7:</font><hr>i want to learn more because i am always mind-boggled by the fact that my cue ball always takes a different direction thanh the one i planned ,
yet at the same time i see the experts ( immonen, reyes, strickland, hohmann etc just taking a quick glance and already calculted the angle of deflection )<hr /></blockquote>
The pros can "see the angles" so well because they have practiced a lot more than most people. It's all about practice. Knowing all of the principles can help too.