Weird, Way Out There, Next Level Chit

[Slasher]

Einstein could spot all of you the 6

 

[Dan White]

See if this helps any although I'm sure Bob will do a better job. Instead of thinking of the cue ball as sitting in a dimple or depression, think of it more like a basketball rolling across your yard which I think is a better representation. Yes, it has to be able to overcome the friction from the blades of grass (the cloth fibers), but it isn't really in a "depression", it is just on a lawn.

Now if you slammed down on the top of the basketball hard enough perhaps you can create a very tiny actual depression such as when you tap in a ball on a table, but that condition doesn't exist during a normal pool game. Even if it did, once the ball is rolling it has now overcome the "hill" it had to climb out of and is back on the flat lawn subject to much easier influence from any force acting upon it (the "depression" does not stay with the ball as it moves but at best is only there when it is at rest, but even that isn't technically correct but it isn't a horrible way to think about it).

There is also identical rolling resistance to the ball regardless of which direction it were to roll so it has no reason to roll anywhere but where the forces that are acting upon it (including Fat Albert) are directing it to roll. Fat Albert is like that one propeller out of the 500 and it has to be able to have an effect on a moving object no matter how minimal it may be.

Here is an example that may also help to conceptualize how the ball's resistance to various forces (including Fat Albert) is highly diminished once it is rolling. If you have ever driven a vehicle without power steering, or where the power steering has gone completely out, you know that it is extremely difficult and sometimes all but impossible to turn the wheels/steering wheel when the vehicle is sitting there stopped, but once you get the vehicle up to speed it actually turns fairly easily.

If you read up a little you will see that Bob agreed that the ball is in a depression caused by the weight of the ball. I think you are talking more about the momentum of the ball in motion while I'm talking about resistance due to the fiber in the ball's path

 

[Dan White]

Think of it like a ship in a perfectly still calm ocean that has neither waves or currents in it and without winds etc. The ship has 500 small propellers in a line all down the ship's keel (longitudinal centerline) from front to back, and 499 of them are all pushing water straight back, and the final 500th propeller, the one dead center on the keel longitudinally, is mounted such that it is propelling water perpendicular to the others, in this case propelling water to the right instead of rearward like all the others. Do you think that ship is going to track exactly dead perfect straight over distance? That is a crapload of water resistance (among other things) that one little propeller is having to overcome just like the friction of the cloth.

The fat man is like that one little propeller. While that one little propeller isn't able to have a massive affect on the course of the ship, it has an effect none the less and the ship will track on a line that is very, very slightly curving to the left, and the fat man's gravitational pull is likewise going to change the cue balls direction ever so slightly as well. You may not be able to tell the ship isn't traveling perfectly straight it its first 100 yards of travel because the effect has been so minimal so as to not be observable and perhaps even measurable yet, but it is still happening and is calculable, and it will certainly be very clearly observable and measurable in the path of the ship after it has traveled 1000 miles.

I agree with this but it is not really what I am talking about. Read my other posts to see what I'm saying.

 

[Poolplaya9]

If you read up a little you will see that Bob agreed that the ball is in a depression caused by the weight of the ball. I think you are talking more about the momentum of the ball in motion while I'm talking about resistance due to the fiber in the ball's path

I agree with this but it is not really what I am talking about. Read my other posts to see what I'm saying.

I'm pretty certain I know exactly what you are saying and where/why you are stuck and I just don't think a depression is the best way for you to think about it because once the ball is moving the depression effectively disappears whether it is physically there or not (and I think there is some room for debate on whether it should even be considered a depression or not but that is neither here nor there at the moment) and this is exactly where you are getting hung up. That being the case, I was attempting to give you some other ways of thinking about it that didn't involve a depression (the part you are hung up on that it seems to me is leading your astray) in the hopes that it might help it click but it seems I didn't do a very good job which I suspected might end up being the case but thought I would give it a shot.

How about this as yet another way of considering it. While the cue ball is moving the depression is "following" it perfectly and always staying perfectly centered beneath it such that the cue ball is never having to "climb" the walls of the depression and therefore it is effectively as if the depression is not there. Probably just muddying the waters more.

 

[Dan White]

Einstein could spot all of you the 6

I'm pretty certain I know exactly what you are saying and where/why you are stuck and I just don't think a depression is the best way for you to think about it because once the ball is moving the depression effectively disappears whether it is physically there or not (and I think there is some room for debate on whether it should even be considered a depression or not but that is neither here nor there at the moment) and this is exactly where you are getting hung up.

I appreciate your efforts but I don't think I'm convinced by your argument (maybe I have a hard head). You lost me the first time when you said the ball does not create a depression in the cloth (unless that was someone else who implied that). Let's talk about that for a minute. Remember we are talking about the ridiculous case of gravity from a person's mass affecting the path of the ball. The ball is a weight resting on a compressible material. It has to sit in a bit of a depression at the contact point. Given that, it seems to me that when the ball begins to roll forward the leading surface of the ball will encounter the "edge" of the depression where the fibers are not yet compressed. The compression of the fibers requires work and my contention was that the gravity effect was so small that it would not be able to alter the ball's path due to the resistance from these "elevated" fibers between the ball's current path and the source of the newly placed gravity.

That being the case, I was attempting to give you some other ways of thinking about it that didn't involve a depression (the part you are hung up on that it seems to me is leading your astray) in the hopes that it might help it click but it seems I didn't do a very good job which I suspected might end up being the case but thought I would give it a shot.

I understand how to add vectors, which is what you were demonstrating with the 501 propellers. That's not what I was talking about, again.

How about this as yet another way of considering it. While the cue ball is moving the depression is "following" it perfectly and always staying perfectly centered beneath it such that the cue ball is never having to "climb" the walls of the depression and therefore it is effectively as if the depression is not there. Probably just muddying the waters more.

OK but if the ball is in a depression and is creating a new one by rolling forward then how does a fiber go from uncompressed to compressed? Doesn't the leading edge of the ball have to encounter the fiber and then push it down? I'm happy to be convinced otherwise but this seems logical to me.

 

[Slasher]

I appreciate your efforts but I don't think I'm convinced by your argument (maybe I have a hard head). You lost me the first time when you said the ball does not create a depression in the cloth (unless that was someone else who implied that). Let's talk about that for a minute. Remember we are talking about the ridiculous case of gravity from a person's mass affecting the path of the ball. The ball is a weight resting on a compressible material. It has to sit in a bit of a depression at the contact point. Given that, it seems to me that when the ball begins to roll forward the leading surface of the ball will encounter the "edge" of the depression where the fibers are not yet compressed. The compression of the fibers requires work and my contention was that the gravity effect was so small that it would not be able to alter the ball's path due to the resistance from these "elevated" fibers between the ball's current path and the source of the newly placed gravity.

I understand how to add vectors, which is what you were demonstrating with the 501 propellers. That's not what I was talking about, again.


OK but if the ball is in a depression and is creating a new one by rolling forward then how does a fiber go from uncompressed to compressed? Doesn't the leading edge of the ball have to encounter the fiber and then push it down? I'm happy to be convinced otherwise but this seems logical to me.

 

[Poolplaya9]

It has to sit in a bit of a depression at the contact point. Given that, it seems to me that when the ball begins to roll forward the leading surface of the ball will encounter the "edge" of the depression where the fibers are not yet compressed. The compression of the fibers requires work and my contention was that the gravity effect was so small that it would not be able to alter the ball's path due to the resistance from these "elevated" fibers between the ball's current path and the source of the newly placed gravity.

Doesn't the leading edge of the ball have to encounter the fiber and then push it down?

I don't know that my explanations have heretofore been ideal and someone else could have probably done a much better job. Perhaps one of them will but I thought Bob pretty much already did and said it all it posts 17, 21 and 24 and there isn't really anything else to explain which is probably why nobody else has added anything when there just really isn't anything else to add and it was already put as simply as could be put. I would spend a bit more time on those three posts thinking them out.

Replying specifically to what I quoted above, and trying to word it in yet another way, what you are failing to take into consideration is that the resistance from the cloth to the rolling of the ball is identical in every direction, no matter which direction the ball goes, no matter which direction the ball would change to, just as much in front of the ball as to the side of the ball, absolutely identical all 360 degrees around the perimeter of the "depression", and so the ball is not biased to go any direction other than that dictated by sum of the forces acting upon it. Because of this is why I have been trying to lead you away from thinking about any kind of "depression" because it simply is not part of the direction equation and has no directional influence on a rolling ball.

Going back to my ship example, you are essentially arguing "but there is no way that one propeller pushing from the side (Fat Albert) is going to alter anything, look at all the resistance from the massive amount of water (table cloth) on the other side of the ship that it would have to overcome", but all the while what you are forgetting is that there is just as much water in front of the ship as there is to the side of it, the water is all around the ship equally in every direction, offering the exact same resistance to the ship in every direction no matter which way the ship were to try to go and so the water is not able to influence direction, only force can (for the sake of argument I'm treating the ship as if it were a sphere shape because a non-spherical shape would obviously allow the ship to be influenced in ways and by things that have nothing to do with our discussion).

Because the ocean (table cloth) is not in any way controlling or even biasing the direction of the ship, the ship is going to go in a direction that is solely influenced by the sum of the forces acting upon it, which in the case of my example would be the 500 propellers. What results is essentially a "weighted average" of sorts of all the forces involved which would specifically in my example be the 499 propellers (the hit from your pool stick) that are lets say all pointed at a 0 degree heading, and because they are working in unison are collectively by far the predominant force, and then also that 1 propeller (the gravity from Fat Albert or the breeze from the air conditioner) that was pointed at a 90 degree heading, and the result is the ship is going to end up going in a path that you could think of as having a heading of 359.999 degrees rather than 0 degrees, because that one little propeller has some influence too, albeit small, and so it is ultimately a blended weighted average or sorts if you will (but it will technically be a very slightly curving path rather than a straight one as long as forces are pushing from more than one direction as they were here).

The only thing you are really missing but which is the key to everything is that the table cloth resistance (and ocean water resistance) is the same in every direction, which necessitates that the cloth (or ocean) is not in any way controlling, influencing, or biasing direction, including giving any bias to keeping the ball moving in any certain direction, even one it is already on, and so therefore only the forces acting upon the ball are controlling its direction, and it is the sum of them that controls it (including Fat Albert, and that one odd ball propeller, and the draft of air from the air conditioner register, and any other minute forces that still also have their very tiny bit of "say" or influence as part of the sum of forces).

Put very succinctly, because the cloth would offer identical resistance in all 360 degrees of direction from a rolling sphere, it is just as easy for the ball to change to some other heading as it is for it to continue on its current path, and so any force such as Fat Albert acting upon it is able to have its impact in proportion to the amount and type and angle of force it brings.

 

[Banger]

Meh, he should have practiced for an hour, instead.

 

[Dan White]

I don't know that my explanations have heretofore been ideal and someone else could have probably done a much better job. Perhaps one of them will but I thought Bob pretty much already did and said it all it posts 17, 21 and 24 and there isn't really anything else to explain which is probably why nobody else has added anything when there just really isn't anything else to add and it was already put as simply as could be put. I would spend a bit more time on those three posts thinking them out.

Replying specifically to what I quoted above, and trying to word it in yet another way, what you are failing to take into consideration is that the resistance from the cloth to the rolling of the ball is identical in every direction, no matter which direction the ball goes, no matter which direction the ball would change to, just as much in front of the ball as to the side of the ball, absolutely identical all 360 degrees around the perimeter of the "depression", and so the ball is not biased to go any direction other than that dictated by sum of the forces acting upon it. Because of this is why I have been trying to lead you away from thinking about any kind of "depression" because it simply is not part of the direction equation and has no directional influence on a rolling ball.

Actually, the forces around the ball on the cloth are not the same 360 degrees. You are taking the water analogy too far, I think. Water is incompressible and the resulting vector will be the sum off the forces acting on it. I'd bet that the fibers trailing the ball, after it has rolled over them, remain compressed for a brief time, if not partially so until the table is vacuumed, even.

Going back to my ship example, you are essentially arguing "but there is no way that one propeller pushing from the side (Fat Albert) is going to alter anything, look at all the resistance from the massive amount of water (table cloth) on the other side of the ship that it would have to overcome"

I know what you mean but to be clear I never said that about water. Water is a different scenario. Also, I'm pretty sure the forces on the ship from the water are not the same. The bow has a much larger force acting against it than the port or starbord. The stern will have turbulance additionally resisting forward motion much as the way a car creates a vacuum behind it. This force or drag most likely is smaller than the resistance at the bow.

, but all the while what you are forgetting is that there is just as much water in front of the ship as there is to the side of it, the water is all around the ship equally in every direction, offering the exact same resistance to the ship in every direction no matter which way the ship were to try to go and so the water is not able to influence direction, only force can (for the sake of argument I'm treating the ship as if it were a sphere shape because a non-spherical shape would obviously allow the ship to be influenced in ways and by things that have nothing to do with our discussion).

Because the ocean (table cloth) is not in any way controlling or even biasing the direction of the ship, the ship is going to go in a direction that is solely influenced by the sum of the forces acting upon it, which in the case of my example would be the 500 propellers. What results is essentially a "weighted average" of sorts of all the forces involved which would specifically in my example be the 499 propellers (the hit from your pool stick) that are lets say all pointed at a 0 degree heading, and because they are working in unison are collectively by far the predominant force, and then also that 1 propeller (the gravity from Fat Albert or the breeze from the air conditioner) that was pointed at a 90 degree heading, and the result is the ship is going to end up going in a path that you could think of as having a heading of 359.999 degrees rather than 0 degrees, because that one little propeller has some influence too, albeit small, and so it is ultimately a blended weighted average or sorts if you will (but it will technically be a very slightly curving path rather than a straight one as long as forces are pushing from more than one direction as they were here).

The only thing you are really missing but which is the key to everything is that the table cloth resistance (and ocean water resistance) is the same in every direction, which necessitates that the cloth (or ocean) is not in any way controlling, influencing, or biasing direction, including giving any bias to keeping the ball moving in any certain direction, even one it is already on, and so therefore only the forces acting upon the ball are controlling its direction, and it is the sum of them that controls it (including Fat Albert, and that one odd ball propeller, and the draft of air from the air conditioner register, and any other minute forces that still also have their very tiny bit of "say" or influence as part of the sum of forces).

Put very succinctly, because the cloth would offer identical resistance in all 360 degrees of direction from a rolling sphere, it is just as easy for the ball to change to some other heading as it is for it to continue on its current path, and so any force such as Fat Albert acting upon it is able to have its impact in proportion to the amount and type and angle of force it brings.

I appreciate your time in discussing this silly but fun topic but nobody here has yet explained why my proposed "mechanism" is wrong. Let's not talk about water. We're in agreement about that. Let me try again. Admittedly this is only a guess but it seems logical to me. The ball is in a depression and in order to move out of that depression it has to compress the fibers in front of it in the direction it is traveling due to the force from the cue tip. If we then introduce Fat Albert after the ball is rolling (which was my premise) at a 90 degree angle from the travel direction, my contention is that the fibers on the side of the ball where Albert is standing will have to be compressed in order for the ball to travel any tiny amount in that direction. If the fiber against the ball generates a normal force greater than the force from Albert's gravity, then the ball direction will not travel whatsoever. This is like an activation energy in chemistry like lighting a match or using a fission reaction to kick off a fusion reaction. If you don't provide enough energy then nothing will happen.

 

[Straightpool_99]

Not to mention that a person of serious gravity standing on one side of the table will make the floor sag on that side.

If you have a sufficiently accurate machinist level you can see the bubble moving when people move around, even on very solid floors. I've seen this happen in a big industrial building, and I was frankly shocked that even that kind of floor would move. However, after testing this level on snooker and pool tables, the movement seen in these cases would not impact the balls to any degree a person would notice. All that would be achieved would be driving the mechanic nuts, trying to achieve a level that is immediately lost when he changes position.

 

[Bob Jewett]

If you have a sufficiently accurate machinist level you can see the bubble moving when people move around, even on very solid floors. I've seen this happen in a big industrial building, and I was frankly shocked that even that kind of floor would move. However, after testing this level on snooker and pool tables, the movement seen in these cases would not impact the balls to any degree a person would notice. All that would be achieved would be driving the mechanic nuts, trying to achieve a level that is immediately lost when he changes position.

And of course a far larger effect is when someone leans on the table when they are reaching for a shot. Or climbing up onto the table as they still do in Louisiana. The equipment specs say how much the table is allowed to sag when loaded temporarily by a weight:

Further this surface should have an additional deflection not to exceed .030 inches [.762 mm] when loaded with a concentrated static force of 200 pounds [90.7 kg] at its center. ​

 

[SlateMan]

This explains why the cue ball ALWAYS falls in the pocket if I stick my hand in the pocket to catch the cue ball. The gravitational pull of my hand CAUSES the cue ball to fall into the pocket. So it wasn't my poor stroking ability after all.

[I have trained myself to NOT stick my hand in the pocket.]