Watching The Pros Putt With the Pin In…

[rehmwa]

1 hour ago, DaveP043 said:

Brandel suggests "bouncier", but I wonder if they're slightly larger. 

Brandel suggesting they are bouncier and NOW it's not a benefit......Any collision of this nature is NOT perfectly elastic.  so what if they are relatively bouncier, I'd say the math still suggests a benefit regardless of the CoR.  No collision will ADD kinetic energy to the ball.

They'd have to build flagsticks from flubber to make one that (generally, on average) hurts the cause.  Or mount the stick on a blender head and spin it....

It's like claiming that the rims on a basketball court are the cause of your team getting bad bounces during a game.

maybe, just maybe it's week two of the experiment and the pros are hitting it harder than usual because there's a stick there

 

and ANOTHER thing, if I had a supply of flubber at my golf course, I'd be making golf balls and club heads, i wouldn't waste it on flagsticks

Edited January 31, 2019 by rehmwa

[dennyjones]

9 minutes ago, rehmwa said:

if I had a supply of flubber at my golf course

An old time funny movie!  

[Missouri Swede]

22 minutes ago, rehmwa said:

They'd have to build flagsticks from flubber to make one that (generally, on average) hurts the cause.  Or mount the stick on a blender head and spin it....

I was trying to figure out how to put a pinball bumper mechanism in there. And hide it really well somehow. 

[rehmwa]

38 minutes ago, Missouri Swede said:

I was trying to figure out how to put a pinball bumper mechanism in there. And hide it really well somehow. 

that would be hilarious - you could just see the old timers watch one ball come shooting out of the hole and victoriously claim this definitive proof to take out the pin

N=1

[iacas]

3 hours ago, rehmwa said:

Brandel suggesting they are bouncier and NOW it's not a benefit......Any collision of this nature is NOT perfectly elastic.  so what if they are relatively bouncier, I'd say the math still suggests a benefit regardless of the CoR.  No collision will ADD kinetic energy to the ball.

It's not just about adding energy, though.

The ball spends significantly less time falling - less time "in the air" unsupported from beneath - when the flagstick is in the hole.

Thicker and/or bouncier flagsticks would further reduce this time.

[turtleback]

16 hours ago, Righty to Lefty said:

When he described his testing in his own words it sounded like they were pretty thorough in how they tested things. Not easy to try and put all the information together in a quick instagram video so it did seem like they glossed over the details before they posted their results. Just because they didn't describe it thoroughly as you would like doesn't mean that they didn't conduct their experiment well.

There is not a prayer in the world that his experiment met any standards of scientific reliability.  

REAL science is hard.  That's why we see so little of it.

10 hours ago, Vinsk said:

Well now you seem a bit eager to defend his poorly done experiment. You first stated you were just posting his findings. Now you’re defending them. Ok. Show us where you believe his experiment is scientifically accurate. Show us how is data is accurate. Explain your reasoning. You’re just arguing with nothing to back your side...as usual.

2 words should end the discussion: sample size.

8 hours ago, Phil McGleno said:

You missed the part-I think they edited it out-Where he basically called EriK-I got it right that time-a liar or something. Of course he is latching on-He is a troll desperate to WIN something, anything.

The way I see it the net advantage is still to leave the flagstick in and I can give full weight to the EM study even while ignoring the flaws and it still comes out on that side of things.

@iacas-Do you consider any study conclusive?

Fwiw, I think physics is the wrong lens to assess this - or at least it shouldn't be the only lens.  In relatively short order we will have an enormous body of data on putting with the new rule to compare with the enormous amount of data we already have under the old rule.  If there truly is a measurable advantage of disadvantage it should show up in those aggregates.

[turtleback]

4 hours ago, iacas said:

Thanks for the correction. I was wrong and I’m glad to see they have updated that.

You'll never get anywhere in cyberspace if you admit when you are wrong.  

[Double Mocha Man]

I watch "The Big Bang Theory" so I know about science...

[iacas]

17 minutes ago, turtleback said:

In relatively short order we will have an enormous body of data on putting with the new rule to compare with the enormous amount of data we already have under the old rule.

If you mean from the PGA Tour and ShotLink, I don't think they're tracking whether the flagstick is in or out on a given shot.

18 minutes ago, turtleback said:

2 words should end the discussion: sample size.

Edoardo rolled a lot more balls - a LOT more - I believe, than MyGolfSpy.

Neither seems to have rolled the thousands Pelz has rolled, or the 2500 or so that I rolled, but still. Edoardo rolled 1800? I think. I think he rolled at least 900.

[rehmwa]

16 hours ago, iacas said:

It's not just about adding energy, though.

The ball spends significantly less time falling - less time "in the air" unsupported from beneath - when the flagstick is in the hole.

Thicker and/or bouncier flagsticks would further reduce this time.

The whole thing is the tradeoff between the lost energy and the time you mention.

My point is it would still be a benefit.  just less so.  they can't use bouncier sticks to dispute that. 

(thicker sticks yes if they get big enough, bouncier no)

 

Edit:  if we had the perfect (impossible) case of a purely elastic collision.....you do lose the real estate the stick occupies and the space behind it for the penalty...  but in real life can we get one bouncy enough?  I can't answer this one - so I hate to be absolute about it....  time for more tests.  (I doubt there's a stick bouncy enough  - but it's just opinion)

Edited February 1, 2019 by rehmwa

[iacas]

6 minutes ago, rehmwa said:

My point is it would still be a benefit.  just less so.  they can't use bouncier sticks to dispute that.

Not necessarily. There's going to be some combination of speed and thickness at which point you're more likely to hole putts without the stick in.

Spoiler

 

Without a flagstick, a ball has 4.25-1.68/2 inches to fall to the equator. That's 3.41 inches. Gravity accelerates a falling object, too, so the gains afforded by extra time are exponential. A ball moving at 3 MPH goes ~3.48 inches in 0.066 seconds (Link).

With a 1/2" flagstick, the ball has (4.25-0.5)/2 - 1.68/2 + (4.25-0.5)/2 -1.68 = 1.23". A flagstick that's 3/4" will reduce the distance by 1/4" (the ball travels in both directions), so 0.98".

The first part of the ball traveling - from the center of the ball to the edge of the ball contacting the flagstick - is (4.25-0.75)/2 - 1.68/2. That's 0.91". Note that this is only 0.07" short of the total distance… which makes sense, because (4.25-0.75)/2 - 1.68 = 0.07 - the ball barely fits between the flagstick and the hole.

So the ball has less time to drop initially (1/8"), and then another 1/8" less to drop on the return. The dampening effects of the flagstick - and 3/4" flagsticks are also quite likely heavier and thus have a higher CoR) - only help the ball during the 0.07" when the ball is between the flagstick and the side of the cup.

In total, for a ball to travel 0.98" in 0.066 seconds it would have to be traveling 0.844 mph. Yeah, that's going to be a weighted average, and yes, that's for a ball to get to the equator when it could hit as low as even 7 o'clock and have a chance to go in… but no, the 3/4" change can still detract from the ability to hole the ball over an empty cup. In my experience, flagsticks bleed some energy from the ball, but you're starting to ask it to bleed a LOT. Remember, a putt going 6' by the hole still goes in at the center the vast majority of the time. (Link)

 

None of that even talks about the off-center impacts, which rely even more heavily on this time vs. speed scrubbed from the ball balance.

[rehmwa]

11 minutes ago, iacas said:

Not necessarily. There's going to be some combination of speed and thickness at which point you're more likely to hole putts without the stick in.

 

I wasn't talking about pin thickness and noted that directly (hell, a pin the size of a cup would knock the ball loose every single time - so now it's just a matter of finding the transition point of benefit vs penalty.  So that's the no brainer.)

But In my edit I also acknowledge an analogous point relating to the bounciness of the stick too (i.e., since the stick is a physical presence, then bounciness would also have a transition point too - for the reasons you note).  It's just that I consider the collision to have so much slop, that the tradeoff crossover point, IMO, would be very unlikely.  BUT, it would have to be tested.  Maybe there's a real life stick that's bouncy enough - I'm doubting it. 

The modeling might be to calc the return speed of the ball after the collision vs (essentially a smaller hole) with the ball already descended slightly...  (the bouncier the stick, the more of the initial vel you retain.)

Or, just get a bunch of sticks and try it out.

I appreciate your observations that tie in the physical conditions to the physics.

Edited February 1, 2019 by rehmwa

[iacas]

26 minutes ago, rehmwa said:

I wasn't talking about pin thickness and noted that directly

The thickness has to be a factor, though, even when talking about a 0.5" flagstick, because a 0.5" flagstick of any bounciness is thicker than no flagstick at all.

20 hours ago, rehmwa said:

They'd have to build flagsticks from flubber to make one that (generally, on average) hurts the cause.

They wouldn't. I think you think the flagstick scrubs off much more speed than it actually does.

26 minutes ago, rehmwa said:

It's just that I consider the collision to have so much slop, that the tradeoff crossover point, IMO, would be very unlikely.

I think you'd be surprised at how quickly it can come. The reduction in distance is a very real thing that has to be considered as well (which is why I assumed you were considering both factors, not just making the general point that bounciness matters).

The crossover point isn't as far out as you seem to think. Hell, look at Edoardo's test. His flagstick may have been bouncy and still only 0.5" and he got more rejections with the stick in than out. I have other questions about his data, but that's a big part of the reason why I didn't just discard it. I think he was using a higher CoR stick, in which case I could see him getting those results, even at 0.5".

26 minutes ago, rehmwa said:

The modeling might be to calc the return speed of the ball after the collision vs (essentially a smaller hole) with the ball already descended slightly...  (the bouncier the stick, the more of the initial vel you retain.)

Of course, but even with a 0.5" stick, the hole goes from 3.41" or something to 1.23". It's significant. It doesn't take much "bounciness" to flip the equations. Most sticks are on the "good side" (for the golfer) of this equation, in my testing and experience, but it's not like there's a ton of room.

This putt according to my calculations was going just barely fast enough to miss… and yet with the flagstick in (and not moving from what you can see), the ball stayed out despite hitting dead center:

 

(The Tiger putt was a bit anomalous - the vast majority of the time that shot goes in. The flagstick is moving a tiny bit, the flagstick might have been grippy, letting the ball climb up it a little… whatever. But it shows, IMO, how close these things are. It wasn't going in without the stick in, the math shows that, so the flagstick didn't hurt…)

[rehmwa]

Good stuff.  Thanks - I'd have more fun with this if I didn't have to work.  Means I only have time to muse on it for a short bit.

" I think you think the flagstick scrubs off much more speed than it actually does. "  That's very true, I do think that.  Flag is loose in it's mount, ball hits it, lots of vibration and sound eating up some of the E.  I'd think it's a fairly effective dampener.  (and considering balls that would roll out a good 9 feet sometimes only roll out a couple feet if they make contact........).  But I get your points and have no issues with them.  well made and understood.  They is some evidence that we can infer the transition point is tighter than I was assuming.

 

again - I'm NOT discounting thickness as a factor.  I'm just restricting my comments to CoR.  (i.e., I'm just holding thickness as a constant in 'my' discussion - as the physical dimensions are a key part of the effect due to CoR).

off to lunch

Edited February 1, 2019 by rehmwa

[iacas]

8 minutes ago, rehmwa said:

again - I'm NOT discounting thickness as a factor.  I'm just restricting my comments to CoR.  (i.e., I'm just holding thickness as a constant in 'my' discussion).

Again, you can't just limit it to CoR, because a flagstick out of the hole not only has no CoR, it has no thickness. Both factors weigh heavily.

[rehmwa]

1 hour ago, iacas said:

Again, you can't just limit it to CoR, because a flagstick out of the hole not only has no CoR, it has no thickness. Both factors weigh heavily.

Absolutely I can limit my comments to the CoR alone with the other factors held constant.  You know what an OFAT is.

I see where you're misunderstanding me.  Nowhere in here did I say the flag was "out of the hole".  It's still in there.  Keep it in there, hold the thickness constant.  Vary CoR with all other factors held constant.  I'm pretty sure I've noted that clearly, and agreed that thickness matters, and provided an example to show I understand that very obvious point.  Can't do much more than that.  I'll check out here.  A good conversation.  thanks.

Edited February 1, 2019 by rehmwa

[iacas]

5 minutes ago, rehmwa said:

I see where you're misunderstanding me.

I'm not. I'm also not talking at you and you alone; I'm talking about the whole problem space.

5 minutes ago, rehmwa said:

Nowhere in here did I say the flag was "out of the hole".

Of course you did. You may not have typed those words, but of course that's what you're talking about when you say it's a "benefit." A benefit to what? To putting without the flagstick in the hole.

And I'm simply pointing out that the point at which that crosses the line is closer than you seem to think. Whether we get there by bounciness, thickness of the flagstick, or some combination.

5 minutes ago, rehmwa said:

Vary CoR with all other factors held constant.

Meh, boring. That's a completely uninteresting line of discussion, so I ducked back out to discussing the whole problem space, and pointing out that we're close to the crossover point on CoR now, despite your proclamation that it's still a "benefit." It's not… and again, the benefit is over a hole without a flagstick.

[rehmwa]

Just now, iacas said:

I'm not. I'm also not talking at you and you alone; I'm talking about the whole problem space.

works for me.  we're good then