Physics

[saevel25]

32 minutes ago, Ty_Webb said:

Yes - although I think that's normally the rear axle rather than the front (which is where the wheels turn typically). 

Some front driven cars now have front differentials. Mostly on more performance cars. It helps a lot with oversteering and understeering. 

 

[GreenhornGolfer]

On 7/17/2025 at 1:02 PM, iacas said:

It's still moving, but it's not very fast (which "almost" might cover), and it begins slowing down around P5.5 to P6 in most good players, for a bunch of reasons. The math gets pretty complex pretty fast seeing as how we have two hands, the club is acting on them while we're acting on the club, etc.

Im new to golf as you can tell with my username but I would think that when you're swinging with the driver, you would want it to be moving at maximum speed at P7 when you're coming into contact with the ball. The idea of using the driver is to send the ball the maximum distance possible which means you would want the ball to be moving at maximum speed which means you want the head of the driver to be moving at maximum speed when it hits the ball so that speed will be transferred to the ball. Maximum speed means maximum distance, and Im talking about the driver shot not shots you would take later on where distance is less important. 

 

As I said, Im new to golf so I could be wrong but it makes sense that you would want your club head to be moving at maximum speed if your goal is to send the ball at the maximum distance. 

On 7/17/2025 at 9:22 PM, Carl3 said:

Angular velocity and acceleration caused by torque.

Thank you, that's what I thought it was called, something along those lines from the research I've been doing. 

So if Im correct, the driver has more torque than say, the 9 iron, because it's a longer club and thus it has greater angular velocity. 

[boogielicious]

3 hours ago, GreenhornGolfer said:

Im new to golf as you can tell with my username but I would think that when you're swinging with the driver, you would want it to be moving at maximum speed at P7 when you're coming into contact with the ball. The idea of using the driver is to send the ball the maximum distance possible which means you would want the ball to be moving at maximum speed which means you want the head of the driver to be moving at maximum speed when it hits the ball so that speed will be transferred to the ball. Maximum speed means maximum distance, and Im talking about the driver shot not shots you would take later on where distance is less important. 

 

As I said, Im new to golf so I could be wrong but it makes sense that you would want your club head to be moving at maximum speed if your goal is to send the ball at the maximum distance. 

Thank you, that's what I thought it was called, something along those lines from the research I've been doing. 

So if Im correct, the driver has more torque than say, the 9 iron, because it's a longer club and thus it has greater angular velocity. 

The hands have to slow down to get maximum club head speed at impact. They are essentially braking to crack the whip so to speak.

[GreenhornGolfer]

3 minutes ago, boogielicious said:

The hands have to slow down to get maximum club head speed at impact. They are essentially braking to crack the whip so to speak.

I see, so it must have to do with the shaft being flexible and bending as you swing it. 

[Ty_Webb]

4 minutes ago, GreenhornGolfer said:

I see, so it must have to do with the shaft being flexible and bending as you swing it. 

I think it’s more about conservation of angular momentum. If the hands didn’t slow down you wouldn’t release it and the clubhead would barely be moving faster than the hands. The hands start pulling up and back as you near impact, which makes the club rotate around its own CoM as well as rotating around the system, which makes it move faster, which as you noted is the idea. 
 

You can watch all this happen if you find a YouTube video of a pro golfer face on and go frame by frame you can measure on your screen how far each piece moves per frame. As those distances change that’s acceleration and deceleration. You’ll see the hands slowing down and the clubhead speeding up

[iacas]

9 hours ago, GreenhornGolfer said:

Im new to golf as you can tell with my username but I would think that when you're swinging with the driver, you would want it to be moving at maximum speed at P7 when you're coming into contact with the ball. The idea of using the driver is to send the ball the maximum distance possible which means you would want the ball to be moving at maximum speed which means you want the head of the driver to be moving at maximum speed when it hits the ball so that speed will be transferred to the ball. Maximum speed means maximum distance, and Im talking about the driver shot not shots you would take later on where distance is less important.

As Scott said, I was talking about the hands, or the grip, not the clubhead.

5 hours ago, Ty_Webb said:

I think it’s more about conservation of angular momentum.

Not really. The body isn't a closed system.

5 hours ago, Ty_Webb said:

If the hands didn’t slow down you wouldn’t release it and the clubhead would barely be moving faster than the hands.

I think that's slightly more wrong than right. Just the difference in the radius would have the hands going much slower than the clubhead. And you could still release it with the hands traveling quickly. It's tougher, but again… we're not a closed system.

5 hours ago, Ty_Webb said:

The hands start pulling up and back as you near impact, which makes the club rotate around its own CoM as well as rotating around the system, which makes it move faster, which as you noted is the idea.

Eh… no, not really. If the club rotated around its own COM the handle would literally be going backward a bunch.

[Bob M]

Bachelor of Science in Chemistry here. While my senior thesis was in Organic Chemistry, Physical Chemistry (Physics as it relates to atoms and molecules) was one of my favorite courses. 

[GreenhornGolfer]

I found a video on the physics of the golf swing, it looks like quite a good video. 

 

Edited July 20 by GreenhornGolfer

[iacas]

7 hours ago, GreenhornGolfer said:

it looks like quite a good video.

It's not. 🤣

It's over 90 seconds into a 5-minute video before they say anything about physics, and when they do, they talk about mastering the double pendulum with a definition that includes gravity or something.

Here, @GreenhornGolfer and others: https://amzn.to/3IHnf0N. Buy that.

[Bob M]

16 hours ago, iacas said:

It's not. 🤣

It's over 90 seconds into a 5-minute video before they say anything about physics, and when they do, they talk about mastering the double pendulum with a definition that includes gravity or something.

Here, @GreenhornGolfer and others: https://amzn.to/3IHnf0N. Buy that.

I second @iacas recommendation, although it is not for the math challenged.

[GolfLug]

3 hours ago, Bob M said:

I second @iacas recommendation, although it is not for the math challenged.

..and strictly an academic indulgence.. I've heard from the grapevine that the author never broke 90..😜

[GreenhornGolfer]

So there's been some discussion about how, when using the driver you want your hands to be moving at maximum speed before the club head hits the ball but not when the club head hits the ball, I don't know the exact mechanics but the short answer is that the club head is moving at its fastest when your hands aren't moving at their fastest. 

Anyway, as I said before Im quite new to golf but when using the irons and particularly the putter I believe your hand speed would be different. To the best of my knowledge when you use the irons and particularly when you use the putter, the main purpose isn't to hit the ball the furthest distance but rather to control exactly where the ball goes and thus speed is not so crucial as it is with the driver. 

However, the same principle applies when using the irons and the putter when it comes to torque, the head of the club is going to be moving faster than the grip because its covering more distance in the same amount of time, The technique for using such clubs is just different than it is with the driver because number one, speed is not so important, and number two, the way the driver is constructed, the head is designed to reach maximum speed after, not during, the time when your hands reach maximum speed, unlike the irons and putter. 

[iacas]

9 minutes ago, GreenhornGolfer said:

So there's been some discussion about how, when using the driver you want your hands to be moving at maximum speed before the club head hits the ball but not when the club head hits the ball, I don't know the exact mechanics but the short answer is that the club head is moving at its fastest when your hands aren't moving at their fastest.

The hands of a PGA Tour player reaches peak speed around their belt or waist.

9 minutes ago, GreenhornGolfer said:

Anyway, as I said before Im quite new to golf but when using the irons and particularly the putter I believe your hand speed would be different. To the best of my knowledge when you use the irons and particularly when you use the putter, the main purpose isn't to hit the ball the furthest distance but rather to control exactly where the ball goes and thus speed is not so crucial as it is with the driver.

The iron swing is almost the same as the driver swing.

Putting is a completely different thing.

9 minutes ago, GreenhornGolfer said:

The technique for using such clubs is just different than it is with the driver because number one, speed is not so important, and number two, the way the driver is constructed, the head is designed to reach maximum speed after, not during, the time when your hands reach maximum speed, unlike the irons and putter.

I disagree. Speed is still very important with an iron.

And putting, let's just cut that out. Completely different zip code.

[Ty_Webb]

On 7/19/2025 at 12:25 PM, iacas said:

I think that's slightly more wrong than right. Just the difference in the radius would have the hands going much slower than the clubhead. And you could still release it with the hands traveling quickly. It's tougher, but again… we're not a closed system.

That's a fair point. You could probably release the club without the hands slowing down at all, but you'd have to be applying a force to the hands to offset the force the club would be applying to the hands as a result of the release. Technically possible, but inefficient I would think. With a driver, the difference in radius if everything lines up straight is something like 36" vs 81" (36" arms and a 45" driver). If the hands are going at 25mph, which would be very fast, the clubhead would be moving at about 56 mph, so there is clearly a lot more going on than just the difference in radius. 

On 7/19/2025 at 12:25 PM, iacas said:

Eh… no, not really. If the club rotated around its own COM the handle would literally be going backward a bunch.

In the club's frame of reference, the handle is going backwards. The whole club is also moving though, so you don't see that in the static frame. The rotation of the club is demonstrable from the fact that the hands are moving slower at impact than they were at waist high as you noted. The hands and therefore the grip are slowing down and the clubhead is speeding up. That's because it's rotating. 

[iacas]

45 minutes ago, Ty_Webb said:

You could probably release the club without the hands slowing down at all, but you'd have to be applying a force to the hands to offset the force the club would be applying to the hands as a result of the release.

I didn't say it was unfeasible.

45 minutes ago, Ty_Webb said:

In the club's frame of reference, the handle is going backwards.

That's not what you said. And… be careful there.

45 minutes ago, Ty_Webb said:

The rotation of the club is demonstrable from the fact that the hands are moving slower at impact than they were at waist high as you noted. The hands and therefore the grip are slowing down and the clubhead is speeding up. That's because it's rotating.

Not around the club's COM, man.

[colin007]

I have a master's in Spanish linguistics and I like black holes.

[GreenhornGolfer]

4 hours ago, iacas said:

The iron swing is almost the same as the driver swing.

How about with the high numbered irons such as the 9 iron? Is the swing the same with that?

4 hours ago, iacas said:

I disagree. Speed is still very important with an iron.

If that's the case then I stand corrected. 

4 hours ago, iacas said:

And putting, let's just cut that out. Completely different zip code.

OK, although there is physics involved in the putt too. 

[iacas]

1 hour ago, GreenhornGolfer said:

How about with the high numbered irons such as the 9 iron? Is the swing the same with that?

If that's the case then I stand corrected. 

Yes. The full swing is not that different, and speed is important with all of them. You don't see Tour players hitting their driver 310 and then hitting their 7I 160.

1 hour ago, GreenhornGolfer said:

OK, although there is physics involved in the putt too. 

Of course, but they're nothing like those for the full swing.