Angular Momentum VS Linear Momentum

[Erik]

In the Baseball/Softball world we here a lot about different methods of swinging a bat and how to start the swing. We also here the different ways in generating bat speed from a no weight shift into rotation or weight shift into rotation etc. This can be very confusing and effect the outcome of each hitter. Which is the best method for hitting a ball and creating batspeed the Conservation of Angular Momentum or the Conservation of Linear Momentum?





EL,

[Erik]

Is this something that's not important to know to hit? Is this to much to get into and will just create confusion? PM me let me know.




EL,

[BoardMember]

Erik, are you trying to compare linear mechanics with rotational mechanics using this momentum conservation question?

Is this something that's not important to know to hit? Is this to much to get into and will just create confusion? PM me let me know.




EL,

[Erik]

BM,

I think many can be lead to false assumptions about the two. When making a decision on which will be best in the swing based on physics most don't know which one it is. I know the methods are both used been there done that. I'm at the point of building a better understanding on both for teaching also as a player for myself. This is why I ask. I want to be able to help define between the two when this subject arrises. This has come up in many cycles in my experience with hitters and parent's. The facts can help in explaining rotational and Linear swings IMO. This post might not be for everyone. This discussion could be confusing when digging into it.



EL,

[NewbieBBDad]

Erik, I didn't bother to post a reply because your question was in the wrong context and used the wrong terms so I thought you might have been trolling.

There really isn't any conservation of X momentum physics discussion in a batswing. I think the right question to ask is which type of swing theoretically applies more energy to the ball on impact.

This is purely theoretical. Assuming a batter has the same energy budget and can apply each type of swing efficiently then the rotational swing will be faster.

Simply put, a linear swing applies energy all along the bat at contact. A rotational swing applies more energy at the end of the bat than at the knob. That differential results in a higher bat speed for a rotational swing.

But this is simply theoretical. If a batter is more energy efficient in one type vs. another that could change the analysis. And there are benefits to a linear swing, the energy expended in the swing can be recycled for a running start down first base for example.

[Erik]

NewbieBBDad,

You stated If a batter is more energy efficient in one type vs. another that could change the analysis.


Which one takes the longest to get the barrel moving to the ball from start IYO?



EL,

[jbooth]

Erik, I didn't bother to post a reply because your question was in the wrong context and used the wrong terms so I thought you might have been trolling.

There really isn't any conservation of X momentum physics discussion in a batswing. I think the right question to ask is which type of swing theoretically applies more energy to the ball on impact.

This is purely theoretical. Assuming a batter has the same energy budget and can apply each type of swing efficiently then the rotational swing will be faster.

Simply put, a linear swing applies energy all along the bat at contact. A rotational swing applies more energy at the end of the bat than at the knob. That differential results in a higher bat speed for a rotational swing.

But this is simply theoretical. If a batter is more energy efficient in one type vs. another that could change the analysis. And there are benefits to a linear swing, the energy expended in the swing can be recycled for a running start down first base for example.

Momentum is created by applying a force to an object. If you apply a force that moves an object in a straight line, then to accelerate that object you need to apply more force. Your body is the source of the force applied to the bat. The body is limited in the amount of force that it can apply. The goal is to get as much acceleration and velocity into the bathead as possible.

The body can apply and create more than one type of force. And, it can apply force to the bat in more than one manner. Not, all methods create the same bathead velocity and acceleration.

If you hold the bat in a bunting stance, and push the bathead at the ball, your arms simply cannot apply enough force to accelerate the bathead to 70mph.

If you swing the bat normally, more force can be applied to the bat.

I agree that in theory a linear application of force (pushing the bat in a straight line) could create as much end velocity as a rotational application (create angular momentum and centripetal force). Barry Bonds could probably push a light bat as fast as a 5 year-old could rotationally swing a heavy bat, but that isn't a good argument for linear swinging.

You can apply a small amount of force at the handle and create angular momentum in the bathead that will create more acceleration than an equal force applied to the bathead in a linear manner.

If you don't create angular momentum, you better be able to apply one heck of a lot of force. If the goal is to reach 70mph bathead speed, it can be accomplished using rotation of the body to create angular momentum, but it's nearly impossible to reach that speed without any angular momentum. If your body is primarily moving the bat in a straight line, you can't get much acceleration of the bathead.

Using the rotational method, velocity in the bathead increases by creating angular momentum, by applying force that moves the handle in an arc. This force comes from the large muscles in the body. Using the linear method, the bathead velocity does not increase much if you move the handle in a straight line. Angular momentum can increase the bathead velocity by changing the handle's direction. Bathead velocity only increases when you move the handle in a straight line, if you apply more force. And, if you've already applied all the force available (from arms and linear body shift), then you get no acceleration.

[BoardMember]

The reason I asked is that the conservation of linear momentum doesn't apply to hitting.

Whether linear mechanics or rotational hitting mechanics are used, because the bat head is moving in a circular path to contact it can't be considered linear momentum.

Now, a thrown baseball or bullet fired from a gun can be catagorized as conservation of linear momentum, because it's path is a straight line.

But NO MATTER WHAT, hitting is angular momentum because the bathead is rotation around an axis, whether the axis is moving linearly or not......

So I think the better question was in your reply to NBdad.......

Unfortunately I can't contribute to you thread because I consider linear mechanics as having more to do with the body movements then the bat path.

They both swing the bat rotationally around the axis IMO.

BM,

I think many can be lead to false assumptions about the two. When making a decision on which will be best in the swing based on physics most don't know which one it is. I know the methods are both used been there done that. I'm at the point of building a better understanding on both for teaching also as a player for myself. This is why I ask. I want to be able to help define between the two when this subject arrises. This has come up in many cycles in my experience with hitters and parent's. The facts can help in explaining rotational and Linear swings IMO. This post might not be for everyone. This discussion could be confusing when digging into it.



EL,

[JeepTJ12]

I don't think a batter can ever swing a bat staying in a linear path. The hindrance of the elbows push the bat out and back in to create at least a soft arc. The biggest argument I get in is the path to the ball. I was always taught hands straight down to contact zone. In the overhead camera shot I don't take a linear path but I do take my hands from shoulder height straight to the ball in a side shot. It "feels" like you're just letting the bat drop straight down to the zone. I used to drag my bat when I was around 10 yrs old and my hitting instructor, who is well known throughout the country, told me to swing like I am chopping wood but right before I make contact at the tee level out and then start an upward plane. I hit line drives straight back to the net. Many rotational guys say this is wrong. I was also taught that without drag in my swing I should be able to put my right foot/right elbow (righty) against a wall and when I swing forward with momentum my bat should not hit the wall. If it does I have a drag problem. Many rotational guys say I have a linear swing and it's wrong. If you look overhead, I swing with an arc much like the Pete Rose clip. I like to say I have a rotational mixed with a little linear swing.

[Erik]

BM,

You say you can't contribute to this thread because you consider linear mechanics as having more to do with the body movements then the bat path.
This is why I ask because many believe the swing is a linear bat path that's more efficient in my experience with parents, coaches, and hired paid instructors.



EL,

[Go Cardinals]

Momentum is created by applying a force to an object. If you apply a force that moves an object in a straight line, then to accelerate that object you need to apply more force. Your body is the source of the force applied to the bat. The body is limited in the amount of force that it can apply. The goal is to get as much acceleration and velocity into the bathead as possible.

Jbooth, thats why these guys get early bat speed. More momentum at the beginning the better.

[Go Cardinals]

BM,

You say you can't contribute to this thread because you consider linear mechanics as having more to do with the body movements then the bat path.
This is why I ask because many believe the swing is a linear bat path that's more efficient in my experience with parents, coaches, and hired paid instructors.

EL,

I think the confusion is between two meanings for linear mechanics.

Definition 1- ichiro... body moves forward, weight forward etc...

Definition 2- Pull the knob, knob to ball- lau and cement mixer

Extra- definition 3- pull the knob, hit down, pivot/ squish the bug... etc. Bad teachings, etc (bad coaches).

[jbooth]

Jbooth, thats why these guys get early bat speed. More momentum at the beginning the better.

Baloney, there is no early batspeed, at least in the way Richard believes. Angular momentum affects the bathead AFTER the first change of direction of the knob, which is just after the shoulders start to rotate, and again when the knob is pulled around the body. MLB hitters leave the bathead alone initially. They whip the bathead from the handle, they don't torque the head around, or push the bat. Bat lag, means to leave the bathead lagging behind. They don't try to get it around early. If they did that, they would never be able to check their swing. What do you see on a check-swing? The hips have turned the knob has moved and the bathead is still back. If they applied force to it early, how does it stay back?

[BoardMember]

Baloney, there is no early batspeed, at least in the way Richard believes. Angular momentum affects the bathead AFTER the first change of direction of the knob, which is just after the shoulders start to rotate, and again when the knob is pulled around the body. MLB hitters leave the bathead alone initially. They whip the bathead from the handle, they don't torque the head around, or push the bat. Bat lag, means to leave the bathead lagging behind. They don't try to get it around early. If they did that, they would never be able to check their swing. What do you see on a check-swing? The hips have turned the knob has moved and the bathead is still back. If they applied force to it early, how does it stay back?

So true......Soooooo true.......

It's an HI "fantasy" to apply early torque to the handle via the hands.......

You know, like the Easter Bunny hiding his eggs!

While there may be an Easter Bunny, HE DOESN'T HIDE HIS EGGS!

[Go Cardinals]

Baloney, there is no early batspeed, at least in the way Richard believes. Angular momentum affects the bathead AFTER the first change of direction of the knob, which is just after the shoulders start to rotate, and again when the knob is pulled around the body. MLB hitters leave the bathead alone initially. They whip the bathead from the handle, they don't torque the head around, or push the bat. Bat lag, means to leave the bathead lagging behind. They don't try to get it around early. If they did that, they would never be able to check their swing. What do you see on a check-swing? The hips have turned the knob has moved and the bathead is still back. If they applied force to it early, how does it stay back?

Why do you assume I mean early torque? All I said was early bat speed. The bat (somehow) has to get going early. Video proves this. Again, I am not saying how... I am saying that somehow it happens.

Oh, I just happen to be using Richard videos...

So true......Soooooo true.......

It's an HI "fantasy" to apply early torque to the handle via the hands.......

You know, like the Easter Bunny hiding his eggs!

While there may be an Easter Bunny, HE DOESN'T HIDE HIS EGGS!

I'll show you knew video, since the other one has Richard's biased all over it ():

Do you see early batspeed jbooth and BM? Again, I am not saying how it happens... just acknowledging that it does indeed occur (somehow).


And this:


Look at wright:



And my favorite player:


Then my hero:




I know I'll be accused of being like Richard for this...

Please answer, does early batspeed occur (somehow, I'm not saying how, just asking if it happens). Do you see early bat speed? Yes or no...