which shot spins more???

snipershot said:
I was playing last night when an interesting question was asked: Which shot spins the cue ball more, a draw shot or a follow shot? I have seen and done both with a great deal of spin, but I can honestly say that I have no idea which one puts more spin on the ball. I think we may need some scientific input here.
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Just off the cue tip, the amount of spin can be the same for follow, draw, or English shots. Now, some people might be getting more effective tip offset with a draw shot (whether they know it or not); unless they are tightening there grip, in which case they are probably hitting the CB higher than they think (producing less spin). Also, with a draw shot, there is drag over the entire shot, so the spin is constantly slowing down (unless the CB is hopping, in which case the spin decreases more during each bounce and remains nearly constant in the air).

Another effect of spin is with a English drag shot (e.g., bottom left English), where the drag converts the backspin to forward roll while dramatically slowing the CB's forward speed. During the drag, very little sidespin is lost, so the effect of the sidespin is greater (e.g., when the CB hits a rail).

I hope I answered your questions. For more info on these topics, see:


Regards,
Dave
 
The question shouldn't be about whether there is more overspin with follow that there is with draw but rather how much energy is retained in the forward or backwards motion of the cue ball when it encounters an object ball.

No matter how hard a cue ball is struck with follow there will be no overspin unless there is sufficient resistance to the forward movement of the ball. A follow shot without overspin doesn't mean the cue ball is not spinning. Natural roll is in fact forward spin. True spin is simply the number of revolutions the cue ball will make in a given distance. Since draw encounters much more resistance from the cloth than a follow shot draw can never achieve the rate of spin as follow does over an equal travel distance.
 
snipershot said:
I was playing last night when an interesting question was asked: Which shot spins the cue ball more, a draw shot or a follow shot? I have seen and done both with a great deal of spin, but I can honestly say that I have no idea which one puts more spin on the ball. I think we may need some scientific input here.


Joe
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As Dr. Dave pointed out, the RPMs that the ball has as it leaves the tip depends on how far from center you hit the cue ball and not whether you hit it high, low or on the side.

If you hit the cue ball at 70% of its height, it will start out rolling smoothly on the cloth. That means that the bottom of the ball is not moving relative to the table. If you hit at 30% of the ball's height for draw, the top of the cue ball will not be moving relative to the table as the center of the ball moves away from you. Similarly, if you hit on the left side of the ball at a similar point, the right side of the ball will not be moving relative to the table.

A related brain teaser: A steam locomotive is moving east at 80 MPH. What part of the train is always moving west?

It is possible to hit the ball high enough -- say at 75% of its height -- that the bottom of the ball is moving backwards as the ball leaves the tip. Similarly for draw and side spin. I call such spin "retrograde" since there is a part of the ball moving opposite to the direction of the center of the ball, or relative to the average motion of the ball. Google "mars retrograde motion" for something similar that happens in astronomy.

Bob Byrne points out a way to test whether you get useful "retrograde" follow in his "Advanced Technique" book.

You can get extreme retrograde draw with a masse shot.
 
I've just read through this thread and I think it's awesome...My two cents..if it's worth even that.

In my opinion we haven't defined spin. Both arguments are solid, especially to include the physics information.

To me, spin means the difference a player is able to make over the natural behavior of the ball.

The natural behavior of the ball based on Newton's first law of motion is thus..(copied from Wikipedia since it's been a while for me in the physics realm) "There exists a set of inertial reference frames relative to which all particles with no net force acting on them will move without change in their velocity" The "without change in their velocity" part is my primary focus.

Assuming a ball is struck perfect center ball with a constant initial velocity from the cue it will proceed at what I will call "zero" speed.

Knowing the CB will skid across the cloth for a predefined distance the natural, or Newtonian law of motion, "spin" does not begin until that skid has dissipated. That distance is the norm.

From here we can determine which "spins more".

The number of revolutions per inch/centimeter, either follow or draw, when being struck at zero speed over this determined skid distance will determine which spins more.

If there are more revolutions per inch/centimeter with a follow stroke, follow stroke spins more. To the contrary, if draw stroke precipitates more revolutions reversely over this established distance, draw wins.

Without any quantatative data to support this I can't say definitively, however, if I was a betting man I'd back the draw stroke.

Again, I'm not a physicist, but I feel comfortable speaking on the subject.

I hope the conversation goes on until someone is able to provide mathematical proof.

Thanks for your time and good racks to all...

Mattie
 
KillerCane said:
serious? if the cue ball slows down and then accelerates again its obviously spinning faster at one point than it is moving forward.
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You are absolutely right, but only after contacting an object ball. This kills the ball's forward momentum, but not it's spin, so it can stop as it contacts the ball, and then start rolling forward again as the friction of the cloth turns that forward spin into forward momentum once again. The argument is whether you can get overspin as of the moment when you first hit the cue ball with the cue. As Dr. Dave's video shows it is possible, but probably only very slightly.
 
sfleinen said:
Joe:

Well, one thing "seems" to be sure -- and that is a follow shot doesn't actually generate "spin" on the ball at all -- it merely begins the forward rolling motion of the cue ball *immediately*, rather than sliding for a bit and "transforming" into roll when cloth friction takes over.

Mike Page has an excellent video on this:
http://youtube.com/watch?v=1WzyxhCl0vs
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That video and test are brutal. The shot at 4:52 that he actually focuses on actually jumps at contact and clears the whole bloody piece of sandpaper without contact, no doubt the sandpaper did not move, that would take some serious spin on that smooth ball to create the required wind turbulence to cause the sandpaper that is not in contact with the ball to move... Go figure hitting at the top of a cueball with a non-level cue.

If you do a poor man's version of the slow mo camera and double click play and pause on each shot you can see that the 9-ball he is using as the cueball is getting airborne on every shot which basically nullifies the whole experiment. 5:18, 5:33, every shot.
 
dr_dave said:
Just off the cue tip, the amount of spin can be the same for follow, draw, or English shots. Now, some people might be getting more effective tip offset with a draw shot (whether they know it or not); unless they are tightening there grip, in which case they are probably hitting the CB higher than they think (producing less spin). Also, with a draw shot, there is drag over the entire shot, so the spin is constantly slowing down (unless the CB is hopping, in which case the spin decreases more during each bounce and remains nearly constant in the air).

Another effect of spin is with a English drag shot (e.g., bottom left English), where the drag converts the backspin to forward roll while dramatically slowing the CB's forward speed. During the drag, very little sidespin is lost, so the effect of the sidespin is greater (e.g., when the CB hits a rail).

I hope I answered your questions. For more info on these topics, see:


Regards,
Dave
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Thanks for the good info doc. So all things being equal, draw and follow produce the same amount of spin right?

Joe
 
ok, lets try this: set up an object ball, straight in, one diamond from the end rail to the pocket and see how far you can draw the ball. Next set the object ball at the same spot with the same angle, and see how far the follow carries the cue ball. I guess you could change the distances between the cue ball and object ball as long as both shots are the same distance. I forgot to try this at the pool hall tonight, but I will try it soon. Let me know what you find, or, what you think should happen based on experience or physics.



Joe
 
it does happen ever break a rack with extreme top only to have the cue ball bounce off the rack a few inches and then continue to the back rail or in my case the head rail again



sfleinen said:
Ponytail:

Great reply! We might want to get Dr. Dave to input into this thread, for there are points in the video where there's overspin (the cue ball is spinning faster than the rate of forward motion), versus not.

For example, upon initial impact from the cue, that mark on the cue ball *does* travel backward ever so slightly, but once the cue ball is in motion, you'll notice that the cue ball maintains traction with the table cloth at all times. Especially when you view the high-speed video at 1:10 in; that striped ball is rolling forward, and when the stripe makes contact with the cloth (i.e. as that stripe rolls "end over end"), one can clearly see that the cue ball isn't "spinning its wheels" or doing a "rolling burnout" like the tires on a car. At 1:10 in the video and beyond, up until the point of collision with the object ball, it's merely a rolling ball, maintaining contact with the cloth. It's only after collision with the object ball (equal mass striking another equal mass object results in motion stoppage of the first object, transferring virtually all the forward energy to the second object). But because of the centrifugal force of the spin "wanting" to keep the ball in motion, it stalls there for a moment, spinning in place, until friction of the cloth comes to bear and this spin results in ball motion again.

Humbly, methinks there might be some slight differences in what the term "overspin" means. Most (like myself) take "overspin" to mean that the ball is spinning faster than the forward rolling motion -- like a "rolling burnout" of a car's tires. However, methinks some may define "overspin" to mean that the ball is rolling fast enough that a collision with an equal-mass stationary object isn't enough to not only stop the forward motion, but also the centrifugal roll itself.

Although holding some education in physics, I'm certainly not an expert, and I'd love to get Mike Page's / Bob Jewett's / Dr. Dave's input on this.
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scottyr44 said:
it does happen ever break a rack with extreme top only to have the cue ball bounce off the rack a few inches and then continue to the back rail or in my case the head rail again
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scottyr44:

That is not overspin. That is merely a very fast rolling cue ball, that had its forward motion stopped momentarily by the rack. A basic premise of physics is that a body in motion, wants to stay in motion. The rack certainly stopped the forward motion of the cue ball, but it didn't stop the gyroscopic "roll" or spin of the cue ball. These are two separate motions -- one is roll, the other is forward motion. Sure, one causes the other, but they can be stopped independently of each other. So when the forward motion of the cue ball is stopped, the gyroscopic roll is still there -- and after friction of the cloth takes over, the roll induces forward motion again.

Hope this helps,
-Sean
 
all i was trying to say is you the cue ball will spin foward while not moving forward even in a single ball contact not trying to get over technical.
 
scottyr44 said:
all i was trying to say is you the cue ball will spin foward while not moving forward even in a single ball contact not trying to get over technical.
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No problem, scottyr44 -- wasn't trying to "get technical." Just wanted to help illustrate that with that follow shot on the break, there's two things going on that are related, but also can be separated. There's no doubt that a follow shot results in "follow" after the forward motion of the cue ball is stopped momentarily. That was never disputed. The original question was which type of shot generates more "spin" -- follow, or draw. Then the thread morphed into a discussion about follow itself, and whether the cue ball in that type of shot is spinning faster than its forward motion, to even remotely explain why the cue ball could "stall" upon impact, but then resume forward motion again. Many folks think this is due to the cue ball spinning, like the tires on a car, faster than the car is moving forward (i.e. rolling burnout). In light of the high speed video, I say not, but offer the explanation that if an object is rolling (i.e. spinning) fast enough, it's like a gyroscope -- it wants to "stay" spinning.

Hope this is helpful,
-Sean
 
I didn't read the whole thread, but the practical answer is top will typically result in more spin for the same speed stroke since the maximum tip offset for top will be greater for top spin for the majority of shots on a pool table. This is due to the rails being a bit over 1" high.

On an academic level, at a certain stroke speed with the same tip offset either above or below the center of the cue ball and shooting with a level cue, the initial spin imparted should be virtually identical. Effective spin at contact with the object ball may be in favor of top depending on distance.

-td
 
now i think i understand well i think in top english the ball does not spin faster than the ball is moving, just applying top english helps reduce the normal friction in a shot. whereas a draw shot the ball actually skips all the way down the cloth until contact. so i would say side spin creates the most spin less friction it was a trick question lol good day



sfleinen said:
No problem, scottyr44 -- wasn't trying to "get technical." Just wanted to help illustrate that with that follow shot on the break, there's two things going on that are related, but also can be separated. There's no doubt that a follow shot results in "follow" after the forward motion of the cue ball is stopped momentarily. That was never disputed. The original question was which type of shot generates more "spin" -- follow, or draw. Then the thread morphed into a discussion about follow itself, and whether the cue ball in that type of shot is spinning faster than its forward motion, to even remotely explain why the cue ball could "stall" upon impact, but then resume forward motion again. Many folks think this is due to the cue ball spinning, like the tires on a car, faster than the car is moving forward (i.e. rolling burnout). In light of the high speed video, I say not, but offer the explanation that if an object is rolling (i.e. spinning) fast enough, it's like a gyroscope -- it wants to "stay" spinning.

Hope this is helpful,
-Sean
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A couple of points:

- "Follow spin" does not mean only "overspin"; it means any amount of forward rotation of the ball, even if it's less than "natural roll" (like when the cue ball is struck at centerball or even below center and skids for a distance as it picks up forward spin). The "amount of spin" is not measured by subtracting the amount of the ball's "natural roll". For instance, a fast-moving ball with "natural roll" has more forward spin than a slow-moving ball with "natural roll", even though they're both rolling "naturally".

- Overspin can be produced with follow; all you have to do is hit the ball at more than 70% of its height (there's another 1/8" or so above that before miscue). The reason it doesn't seem that overspin can be produced is that it's hard to see and rubs off so quickly from cloth friction. However, on new slick cloth overspin can carry for several feet.

- The question "which shot spins more" is misstated. It should be "which shot spins longest" or "which shot moves the cue ball more after a head-on collision stops it"? Follow wins by a mile.

pj
chgo
 
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Originally Posted by sde
Is it the part of the wheel that is below the level of the track?
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its the radius of the wheel below the axle. so basically the bottom half of the wheel.
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sde is right; only the "flange" of the wheel (the part below the top of the rail) ever goes in the direction opposite the train's motion.

pj
chgo
 
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