Physics

Poll: 42?

Yes
82.76%
72
No
17.24%
15
Total: 100% 87 vote(s)
add spin/rotational velocity and rotational inertia somewhere?
(Feb. 08, 2011  3:36 AM)Mc Frown Wrote: add spin/rotational velocity and rotational inertia somewhere?
Kk, throwing that under the Foundations section and probably Metal Weights section. Do you have any sites that I can throw in as citation and a quick description by cahnce?
My brain exploded for a sec.
You must be a genius.
Reviving this thread. After Kai-V's permission I am writing this small article. I hope it is not too bad. I am still learning all this in my classes so I might have done some errors. So please do tell me if anything has gone wrong.
Quote:Reason why sharp tips have bad balance

Concept of Normal reaction: Every action has an equal and opposite reaction and normal reaction is commonly known as the reaction for the force of gravity. When an object placed over other object does not 'sink' in it, normal reaction is the force which prevents it from 'sinking'. It passes through the common plane of the two surfaces in contact.

With the help of Normal reaction, the reason for the bad balance of the sharp tips can be explained:

The over-complicated explanation

The simple explanation
I hope it was not bad.

Warning: Large images
If you are going to use the "normal reaction" throughout the article it would be a good idea to define it first.

The drawings need significant work. When illustrating force vectors the length of the line indicates the amount of force - and you've got some mismatched force vector line lengths.

The last drawing is truly confusing. Please present the horizon/surface as a horizontal line, tilt the bey, and show the normal force pointing straight up. You may also want to exaggerate the tilt of the bey to make it more clear what is happening - and in order to do so I would suggest changing the bey in the illustration to use a 230 track.
To be honest, I barely remember being explained what N (Normal) was, but I suppose that something quick would be good. The last image seems clear enough.
I've just started learning this thing on Sunday(yesterday), as of yet, but shouldn't "center of mass" be termed as "center of gravity" as it is more commonly referred to as?
Or am I missing something?

EDIT-
Reasons- Just to make it more simple to understand. Smile
The whole thing is grossly overcomplicated and neglects to actually draw any distinction between the forces at work on a sharp tip vs. any other tip.

Frankly the whole thing is better explained by saying:

Have you ever tried to balance a sharpened pencil on its tip? It doesn't work.

Look, the physics principles at work here are very simple:

When the gravitational force vector acting on the centroid (center of mass) of an object falls outside of the footprint of its base it will tip over. The sharper the tip, the smaller the footprint is over all angles the bey makes with the stadium, the easier it is to tip over.

We can illustrate this without resorting to an inclined surface, or making any mention of additional perpendicular forces. Just show a bey slightly tilted on a level surface, draw equal force vectors, then show the direction of movement with a velocity vector.
Arupaeo That is the reason i said in the start that I may make mistakes. I am only a tenth grader after all Tongue_out .Honestly before this i never knew that the lines represented the magnitude of force. Secondly, i agree that the diagrams are not good enough and that is because i made them in a hurry. I will try to make better diagrams or rather i will just draw it and then take a snap of it. Next, leaving the complications aside, are the things written 'right'? I really dont want to mess up things like this during exams so it is better to be corrected here. And should i rewrite the whole thing and use whatever you said or should i just include your explanation in what i wrote?

I will write a short explanation of normal reaction.

About the last image, i showed the tilt to represent the stadium slope. Should i change that as well?

Jsb Centre of mass is that point in multi-particle mechanics which is a representative of all the particles in the system and this is the point from which the gravitational acceleration is assumed to act on the body hence it can be called as the centre of gravity.

EDIT: I have written a short summary of Normal Reaction and also I have added a short and simple explanation of the toppling as Arupaeo said. I will make the diagrams soon.
Google's got great diagrams, when I checked recently. So just in case you want to use them... Smile
Also, the reason to refer to center of mass as center of gravity, is only because I've seen people use "center of gravity" more often. I mean, it is a more famous term. But of course, scientific terms should be used... Tongue_out
Both of them are scientific terms Tongue_out but in this case Centre of mass will be more appropriate(acc. to me) because gravity acts through the centre of mass always and also because the centre of mass is the axis about which the bey topples(and also spins Grin).
I will post this here since people can indeed reasonably wonder what the hell we are talking about when we mention "Flywheel Effect". The following article is not complete and there might be some slightly incorrect parts since asafarakaratara had suggested several changes, but I think it still offers a decent description of the Flywheel Effect :

Quote:HEAVY WHERE IT COUNTS
Or how weight distribution works.



Usually, an excess of weight can be detrimental in movements: it can cause too much friction and sometimes completely cease a displacement, for instance. This is due to the force of gravity being too strong. If you take this force created by the mass and make it spin on a horizontal level compared to the usual vertical, weight can be very helpful, but its position around the axis of spin is most important depending on the style of play. If we observe the two extremes of weight distribution, most of the mass can be either on the circumference of the spinning top, or at its centre.

In the first case, considering the velocity given to the Beyblade with its launch, the positioning of the weight on the perimeter will generate a flywheel effect. This phenomenon can be described as the pulling of the centripetal force on the mass that is already in movement around an axis. This means that if more mass is away from the centre, the force of its rotation will give more energy for the following portion of rotation, which in return gives energy to the other portion of rotation, etc. The flywheel effect can be further understood by a similar sort of activity : pendulum rotations with gravity. If we give a pendulum a very strong push to make the mobile object at the end of the string move around the fixed part, on its ascension portion the movement will become slower, however it will accelerate on its descent due to the pull of gravity, which is directly its weight. When you return to the subject of spinning tops however, it is possible to almost completely ignore gravity (especially if the weight is well balanced left and right) because it does not act in pulling back the force created from the rotation and the help weight on the outside does. Instead, only wind will make negligible friction, and it is mostly only the friction from the tip rotating on a surface that will cause the movement to cease. Of course, the initial launch needs to have considerable power though.

As for the positioning of the mass in the centre of a spinning top, this distribution will not be used for stamina-type Beyblades, contrarily to the distribution of weight on the circumference, because the former of course pushes down directly on the friction point of the tip, which has more chance to slow the top and make it lose stamina. Weight in the middle will be used for the other types of Beyblades, mostly defensive ones, but some attack-type blades as well. In most cases, the way the weight is placed at the centre of a spinning top will simply produce a sensation of higher mass in general, but more importantly, this sensation will create bigger impacts with some aggressive Beyblades, or it will make it more immobile if it uses a defense Bottom. It is more difficult to dislodge an object that is very heavy, and this overall heaviness of something can easily be compared to the core of a Beyblade. There will be more resistance on the part of the defensive top than if it had weight distributed mostly anywhere. Sometimes, a Metal Face can be added for a particularly vast improvement in defensive capabilities.
THANKYOU!

Gonna save that to my useful links for when I explain stuff Smile


EDIT: Physics dropout reporting in.
That whole quote is terrible, and many things are just plain wrong.

Quote:As for the positioning of the mass in the centre of a spinning top, this distribution will not be used for stamina-type Beyblades, contrarily to the distribution of weight on the circumference, because the former of course pushes down directly on the friction point of the tip, which has more chance to slow the top and make it lose stamina.

This one was my favorite though. Evidently gravity ceases to exist if weight isn't placed directly over a fulcrum.

Total garbage.
I think it's just implying that if weight isn't directly over the point of friction, the force upon that point is lower.


I did drop out of physics in the last year though sooo...
This article is similar to the one written by Nic in this thread.

And since he has mentioned about moment of inertia and torque,you could also mention that when the weight is focused on the circumference, the moment of inertia is higher and when the weight is focused near the centre, the moment of inertia is lower.
And while battling the same opponent with the same tip, the torque of friction and the torque of opponent remains same. Therefore since Torque = Moment of Inertia x Angular acceleration(retardation in this case),
1) the bey with higher moment of inertia will have a lower angular retardation
2) the bey with lower moment of inertia will have a higher angular retardation
As a result, if the bey has an initial angular velocity of ω, it will take longer time to stop in case 1 and will stop comparatively faster in case 2. Hence, in case 1 it has a higher stamina and a comparatively lower stamina in case 2.
The higher the moment of inertia, the better the stamina hence weight focused outside is preferred for stamina types.

EDIT: I hope I did not further complicate it
(Feb. 11, 2012  7:24 AM)th!nk Wrote: I think it's just implying that if weight isn't directly over the point of friction, the force upon that point is lower.

Right, that's the part that is completely and utterly wrong.

It's like saying that if you stepped on a scale holding a brick in each hand, that your weight as measured by the scale would decrease if you held your hands (and the bricks) out to your sides rather than close to your body and directly over the scale.
At certain places in the thread it has also been mentioned that more the area in contact, more the friction. And in my physics class I have been told that friction is 'independent' of the area in contact. What exactly is right?
In physics class, this question is posed with 2 non rotating surfaces like the short end or long end of a block of wood. The correct answer for that case is that the friction is the same regardless of whether you pull the block on the short end or the long end because the greater surface area decreases the pressure acting on that surface area.

In beyblades, we have rotating surfaces that contribute additional movement to the bey in proportion to the surface area in contact with the stadium floor. The resulting transformation of rotational energy to horizontal kinetic energy results in a greater degradation of the bey's total rotational energy (stamina in our world) for tips that make more contact with the floor.

People shorthand or don't really understand the mechanics behind this decrease in stamina and attribute it to "more friction".
(Feb. 11, 2012  7:35 AM)Arupaeo Wrote:
(Feb. 11, 2012  7:24 AM)th!nk Wrote: I think it's just implying that if weight isn't directly over the point of friction, the force upon that point is lower.

Right, that's the part that is completely and utterly wrong.

It's like saying that if you stepped on a scale holding a brick in each hand, that your weight as measured by the scale would decrease if you held your hands (and the bricks) out to your sides rather than close to your body and directly over the scale.

Good point. Perhaps you'd be able to explain the flywheel effect a bit better then, and to explain how metal faces/HMC's are bad for stamina?

You seem to have the understanding (obviously, I have no way to be sure as I simply cannot get my head around physics (trigonometry, calculus, etc, chemistry, biology, english, I can do. Not Physics, though)), so perhaps you could clear this up for us all?
I apologise if you already have and I have missed it, of course.

Hmm so I was right then. That means the torque of friction is what reduces the spin and not friction itself. Isn't it?
Sorry to revive this thread, but I strongly believe that my post needs to be read. My Physics draft is less confusing and much more helpful and simple than the OP's.

Introduction to “BeyPhysics”

In Beyblade, Physics is often used to aid competitive players. Competitive customs are made because of Physics. For example, why do most stamina customs have their weight externalized? Often, players will build a competitive custom without knowing what its true use is.

Physics
Competitive Customizations often incorporate Physics.

Use of Physics in Smash Attack Combinations: In Competitive Smash Attack Combos, one of the basic fundaments of physics can is applied: "As an example of varying pressures, a finger can be pressed against a wall without making any lasting impression; however, the same finger pushing a thumbtack can easily damage the wall. Although the force applied to the surface is the same, the thumbtack applies more pressure because the point concentrates that force into a smaller area." This basic fundament states/determines why a MW like Flash is used for attack rather than a MW like Duo. Flash has several small notches on the perimeter of its MW. It is these small notches that focus force into smaller points, creating more pressure and allow for critical hits. The Weight distribution of a smash attack combo should be focused towards the MW’s perimeter. While focusing weight towards the center may give a higher spin velocity, this isn’t much use to Smash Attack Customs. A higher Spin Velocity does not necessarily equal a more powerful attack. Spin Velocity and Rotational Velocity are different things. Spin Velocity constitutes the amount of revolutions per unit time. Rotational Velocity is the linear speed component of a given point on a rotating body at a given instant. Spin Velocity creates Rotational Velocity, and Rotational Velocity is what creates Rotational Inertia, which is what assists in Attack (given a point on the perimeter of the spinning body.) Spin Velocity can increase Rotational Velocity (MF), though to do so in Beyblade is less efficient than increasing your Rotational Inertia through outside focused weight. Rotational Inertia is the force behind an Attack, (Rotational Inertia is basically a combination of Rotational Velocity and Mass.) In the realm of Attack, Spin Velocity is never a bad thing, but never should Rotational Inertia be forgone in its sake.

Use of Physics in Upper Attack Customs- Although Upper Attack is irrelevant to the MFB metagame, Physics still impacts many customs using Upper Attack. Upper Attack Beyblades should be focused on maintaining a high spin velocity as well as being low in height. If the opposing Beyblade has a higher spin velocity, then in will be harder/more difficult to lift them (which is the main purpose of Upper Attack customs.) Thus, it is necessary to make a Upper Attack Custom as Low and as Heavy as possible.

Use of Physics in Force Smash Customs- In Force Smash customs, weight generally needs to evenly distributed in order to maintain a higher spin velocity. The Beyblade utilizing Force Smash must be tall also.

Use of Physics in Weight Based Defense Customizations- Competitive defense customizations often rely on high spin velocity to survive heavy hits from attack type Beyblades. For weight based defense customs, generally the heavier an object is, the harder it is to move that object. For example, an attack custom such as (MF Flash Pisces S130 R2F) would have a very hard time knocking out a defense combo such as (MSF-H Wyvang Wyvang BD145 MB/CS). Additionally, more weight means higher spin rate.

Use of Physics in Grip Based Defense Customizations- Grip Based defense customs apply a tremendous amount of friction. Generally, the more friction an object has, the harder it is to move it. For example, an attack custom such as MF Flash Pisces GB145 R2F will have a hard time KO’ing
MSF-H Revizer Revizer E230 CS.

*The Use of Spin Velocity in Attack and Defense Customs- Spin Velocity makes a Beyblade complete more spins whereas Rotational Inertia allows a Beyblade to retain spin and make its Attack and Defense Better. This is why most Defense Customs and some Attack Customs use a MF-(H)/MSF-(H).

*The Use of Spin Velocity in Compact Customs- Although irrelevant to MFB, compact customs incorporate Physics as well. A compact combo focuses on having high spin velocity. The shape of compact combos are generally small and thus, compact. The majority of a compact combo’s weight should be distributed toward the center. As a result of this, compact combos have incredibly high spin velocities.

The Use of Physics in Stamina Customs- Competitive Stamina Type Beyblade’s have their weight externalized around the perimeter. Most Stamina Metal Wheel’s have a hollow and light center. As a result, this produces what is known as the Flywheel Effect, which is the ability for a rotating object to increase its rotational velocity with the use of its own momentum. The flywheel effect is the continuation of oscillations in an oscillator circuit after the control stimulus has been removed. It should be noted that Rotational Inertia retains spin, NOT Spin Velocity. That is why most good stamina wheels are fairly wide. Stamina customs (usually) use a MF-L to keep their weight externalized.


* Real World Example of Rotational Velocity:- Spin a ball or a coin or virtually anything. It will complete vastly more revolutions per unit time than the Earth does, but the perimeter of the Earth is moving much faster (1037.5646 mph/1669.8 kph). Would you rather get hit with a beam moving at that speed or the speed of the perimeter of your ball? Yeah. Obvious answer. That’s Rotational Velocity. The force behind the hit is increased with outside-focused weight, so the wider and heavier (on the perimeter) the better.


Overall

Physics has impacted Beyblade from the very beginning. It plays a key role in determining which Beyblade’s are competitive and which ones aren’t. As a result, every competi
Reviving this thread to post some stuff that I had written few days back.
Huge article ahead (Click to View)

I probably wasted too much time for something that hardly anyone would read.
Anyway, suggestions/comments are appreciated(unless you are going to put tl;dr)
I don't think the problem is going to be a lack of readers so much as a lack of apt commentators. The article is very interesting, but also very dense. It might be a little too technical, considering the target audience, especially the first section (not the terminology), and I can't say I fare that much better. But I have a few comments.

When I wrote up my Energy Transfer draft, it sparked a debate that filled up the majority of the comments; that is "angular velocity vs. spin velocity." On one hand, you had spin velocity being a terrible term--not a real term--coined by the WBO, and on the other, you had angular velocity being too technical a term. Eventually, "rotational velocity" settled as the compromise between correct and simple. So, if you want to use that, I do believe it's a fair compromise.

Angular velocity: I do believe velocity implies a sense of direction, as to differentiate its definition with RPM, for example.

Other than that, I guess the article could use more concrete example. For example, I've always explained Tornado Stalling to myself as a phenomenon similar to driving a car down a curve: The faster you drive, the more your car gets pulled out the curve, just as the faster a Beyblade spins, the more your it gets pulled up the curve, and as it slows down, progressively falls back down as well, as the Beyblade no longer generate enough force to counteract the force of gravity.

The rest, as far as I'm concerned, really depends on whether you posted this in the Physics thread because there was one, or because you don't intend for it to get on Beywiki.

- There is always a space separating parentheses (like this, and not(like this)).
- You shouldn't use contractions (unlike what I just did) when writing an article, nor should you use direct speech (first person). You should use indirect speech instead (third person).
- When you say you're going to "talk more about a subject later in the article," redirect to a specific section instead. However, in this case "later" was probably meant as a unit of time, as these sections haven't been written yet.

Other than that, a few grammatical errors here and there, but that can wait until the article is in its final stages.

Still, good work.
First of all, thanks for the comments Nocto.

While writing the article, I had realized that it wasn't as easy to understand as it should have been. But then again, I'm not too good at explaining things either. And I tend to make things too technical, which is exactly what has happened here.

TBH I wrote this article to make sure that I myself had understood all the stuff that I mentioned above and was able to give a proper explanation from a Physics perspective. But if it can be made Beywiki quality with editing, then I'll try my best to make it meet the standard. I do have to make some changes to it anyway.

I'll change the angular/spin velocity to rotational velocity when I post the edited version because there are still some more changes I need to make. I'm thinking of including two sections, one which explains the section in simple words and one that has all the technical terms in it.

BTW I'm not very good at grammar so I'll have to leave that part to the other members here.