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The Cause Of Spin

  1. Jul 23, 2004 #1
    Can any one here explain me as to what causes the spin of a billiard ball and is this 'spin of a ball', in any way, related to the spin of the 'celestial balls'?
  2. jcsd
  3. Jul 23, 2004 #2
    Well the spin of the billiard ball is caused by the force being applied in a way that does not put the direction of the impulse through the center of gravity of the ball, thus applying a torque around said center of gravity.
  4. Jul 23, 2004 #3


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    Not necessarily; if a centered impulse causes the ball to slide, the frictional force from the ground in the aftermath will provide a torque.
    Eventually, the ball will go into "pure rotation", i.e, the contact point velocity on the ball is zero.

    (On second thought, read differently, your answer covers this aspect as well..)
    Last edited: Jul 23, 2004
  5. Jul 24, 2004 #4
    Does it mean that no involvement of our mind(apart from 'physical' hitting the ball) is necessary to produce a spin motion in the ball and also make it take the intended direction before it strikes the object ball?If mental involvment is necessary,what sort of calculation is to be done mentally so that two things(spin in the ball and the required direction) are achieved without fail?Please let me know if physics has any concrete answer to the question in the contest.
  6. Jul 24, 2004 #5

    Doc Al

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    I'm not sure what you are asking here about "mental involvement". Assuming the ball starts at rest, what makes it spin (as has been explained) is a net torque about its center of mass; what makes the ball accelerate is a net force. The degree of "mental involvement" required depends upon your skill in billiards, I presume. :smile:

    Do a web search on the physics of pool or billiards and you will find lots of interesting discussion on this topic.

    (Please don't post the same question in multiple forums, or multiple times in the same forum.)
  7. Jul 25, 2004 #6
    My reference to the required 'mental involvement' takes it's source in the 'strange out come ' of my years of research on the subject of 'aiming'........The strange result is that human mind(irrespective of age,sex etc.,) does require to complete a simple (seemingly.... but complex in depth) routine-a 'mental process',along the line of aim, before we strike the ball to produce a spin motion in it and more amazing is that the 'routine' is to be applied(mental completion) in the opposite (back ward) direction of the line of aim in order to get a 'spin stroke' and that if the same routine is applied along line in the same forward direction to get a 'spin less stroke'.

    Also...the results show that it's just impossible to produce the 'spin motion' in the required direction without the specific 'routine' (mental process) duely completed by the mind.

    Thus,apart from mechanical explanations of cause of spin,I feel,it can be proved that a specific mental process i.e the mind is the real cause of spin.

    And as for 'celestial spin',it's known to all that one of the very fundamental questions of cosmology,the cause of spin of the 'celestial balls'-the erath and the other bodies,still remains unanswered(satisfactorily) by modern science.The question has been set aside with some 'vague' explanation......

    So....based on my research results,it could be convincingly proved that a ball (terrestial or celestial) DOES require a MIND at work with a SPECIFIC process.Then it's not hard to imagine whose MIND is behind the spin of the earth....in other words..doesn't this conclusion lead to the proof of 'Existence Of God' ? and is it not for us to conclude (philosophically) what's true is "mind over matter"?

    Hope I made my point clear.
    Last edited: Jul 25, 2004
  8. Jul 25, 2004 #7


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    Yes; as far as you are able to..
  9. Jul 25, 2004 #8

    Tom Mattson

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    Unfortunately, your feelings on the subject are not enough. What possible reason could one have for supposing that things did not spin before minds evolved?
  10. Jul 25, 2004 #9
    What he is saying is God made the celestral bodies spin, cause we were not here and we make pool balls spin cause we invented them. :surprise:
  11. Jul 26, 2004 #10

    A plane + Triangle inequality theorem = spin.
  12. Jul 26, 2004 #11
    Suppose I could, with the help of my 'discovery', change a 'novice' into a 'champion' (i am ready to take up the challenge) relatively in a short span of time,or if I could make the masters of the game accept the truth of my theory........ ?Woudn't it be the best proof of my theory? Then,wouldn't all the mechanical explanations (the very 'motion' related explanations) given by physics(modern science) stand disproved?
  13. Jul 26, 2004 #12
    Newton's third law.

    This person is applying Newton's third law.

    Goes like this.

    Newton's third law < Newton's third law + Newton's third law
    Triangle inequality theorem.

    This is his spin formula.

    (c)Action < (a) Reaction + (b) Reaction,
    (a)Reaction < (b) Reaction + (a) Action,
    (b) Reaction < (a) Reaction + (c) Action.

    Now the idea present in the Triangle inequality theorem above is that there are plural points(a), (b), (c). Plural, not singular. Less < Greater = Plural.

    My proff is. Can Newton's third law agree with the Triangle inequality theorem ? Of course it does. Right ? :rofl:

    So there you be. The spin this person is mentioning. Present from none other than action. We equal action. So...where does this conclusion lead too ? God perhaps ?
  14. Jul 26, 2004 #13
    A billiard ball spins because of the friction of the table and the difficulty of hitting the ball exactly perpendicular to dead center. Likewise, almost every celestial object displays spin for similar reasons. What is more, objects such as the earth are not nearly as solid as a billiard ball. Their internal constituents are constantly in motion, just as the atoms in your body are constantly in motion, sometimes at relatively high speeds. All of these influences, both internal and external, tend to impart spin.
  15. Jul 26, 2004 #14
    yeah, nice theory... let's try it out...
    i'm going to convince my girlfriend that you don't exist, and then you tell me whether or not you dissapear, okay?
    Last edited: Jul 26, 2004
  16. Jul 27, 2004 #15
    Last edited: Jul 29, 2004
  17. Jul 27, 2004 #16
    where did you even get this idea from anyway?
  18. Jul 27, 2004 #17
    A lack of friction against the table? :wink:
  19. Jul 27, 2004 #18

    Tom Mattson

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    Pool balls don't spin because we invented them. They spin due to unbalanced torques.
  20. Jul 27, 2004 #19

    So he needs your answer not me, You are both thinking on different wavelengths, I am just pointing out which one he is on. In answer to your answer, I would agree and no spin is a 8 ball stait in the pocket. :smile:
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