RE: Physics - Mc Frown - Feb. 08, 2011
add spin/rotational velocity and rotational inertia somewhere?
RE: Physics - Gibraltor - Feb. 08, 2011
(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?
RE: Physics - chaosfreek - Mar. 05, 2011
My brain exploded for a sec.
You must be a genius.
RE: Physics - Justaway - Jan. 09, 2012
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
First up, I’ll explain about the moment of a couple.
The Normal Reaction of any object generally passes through the center of mass. If you apply a force on an object placed on ground, parallel to the ground, the normal reaction shifts to the direction of point of application of force in order to prevent the object from toppling.
For example, consider this block. When no force is acting, the Normal passes through Centre of Mass but when an external force acts, the normal shifts towards the right by distance ‘a’ to create a moment(Nxa) to prevent the object from toppling due to the Moment of External Force(Fxb).
Now consider the sharp tips. When the beyblade with a sharp tip is hit with other beys, there is an external force acting on them which pushes the bey away from the centre. When it shifts, away from the centre, the normal reaction makes an angle with the incline of the bey. At this point, the normal reaction also provides a moment (Nx height of Centre of Mass.sinÏ´) to the bey and thus, the bey goes on inclining at one side.
If it comes in contact with the opposing bey in this condition, the Normal as well as the downward force exerted by the bey in the center cause it to tilt even further. Finally the bey loses balance completely and stops after floor scraping. However, during the time when the bey is getting inclined, if an external force acts on it and creates a moment opposite to that created by the normal, it can regain its balance. However the chances of this happening in the stadium are almost negligible with other defense and stamina types which tend to stay in the center and in case of attack, the force exerted would be large enough to throw the beyblade out of the stadium.
In case of other tips (D series or F series) the surface area of the tip is comparatively bigger. Hence in case of external force acting on these tips, the Normal Reaction shifts itself in order to balance the moment created and hence they do not lose their balance as easily.
Sometimes, in case of WD, the moment of Normal reaction completely balances the moment of the bey’s weight (and sometimes even of an external force) as it loses spin and it results in the bey staying balanced at an angle even after it ceases to spin. This attribute of WD tips makes it useful for the wins in the last few seconds of the battle.
The simple explanation
For the two surfaces in contact(Tip and Stadium floor), if the weight of the bey acts through the centre of mass and the tip, the normal reaction also passes through the tip and the centre of mass and counter-balances the weight of the bey. In this case the Normal passes through the centre of mass and does not produce any torque. Hence the bey remains balanced.
However if the tip is sharp(like all tips of S series), the weight of the bey generally does not pass through the tip and hence the normal reaction being away from the centre of mass, creates a torques which creates an incline in the bey and finally it loses balance.
I hope it was not bad.
Warning: Large images
RE: Physics - Arupaeo - Jan. 09, 2012
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.
RE: Physics - Kai-V - Jan. 09, 2012
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.
RE: Physics - Janstarblast - Jan. 09, 2012
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.
RE: Physics - Arupaeo - Jan. 09, 2012
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.
RE: Physics - Justaway - Jan. 09, 2012
Arupaeo That is the reason i said in the start that I may make mistakes. I am only a tenth grader after all .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.
RE: Physics - Janstarblast - Jan. 10, 2012
Google's got great diagrams, when I checked recently. So just in case you want to use them...
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...
RE: Physics - Justaway - Jan. 10, 2012
Both of them are scientific terms 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 ).
RE: Physics - Kai-V - Feb. 11, 2012
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.
RE: Physics - th!nk - Feb. 11, 2012
THANKYOU!
Gonna save that to my useful links for when I explain stuff
EDIT: Physics dropout reporting in.
RE: Physics - Arupaeo - Feb. 11, 2012
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.
RE: Physics - th!nk - Feb. 11, 2012
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...
RE: Physics - Justaway - Feb. 11, 2012
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
RE: Physics - Arupaeo - Feb. 11, 2012
(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.
RE: Physics - Justaway - Feb. 11, 2012
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?
RE: Physics - Arupaeo - Feb. 11, 2012
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".
RE: Physics - th!nk - Feb. 11, 2012
(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.
RE: Physics - Justaway - Feb. 11, 2012
Hmm so I was right then. That means the torque of friction is what reduces the spin and not friction itself. Isn't it?
RE: Physics - Plastics Lover - Jul. 06, 2013
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 “BeyPhysicsâ€
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
RE: Physics - Justaway - Jan. 07, 2014
Reviving this thread to post some stuff that I had written few days back.
Quote:First up, explanation of some of the terms used in this article.
1. Torque = Torque is the tendency of a force to rotate an object about a particular axis. It is the cross product of radius vector connecting the axis of rotation to the point of application of the force and the force vector. The direction of torque is given by using the right hand rule for cross products.
2. Moment of Inertia = The moment of inertia of a body is the ability of the body to retain its rotation when it is already rotating or the ability to oppose being rotated when a torque acts upon it.
3. Angular momentum = Angular momentum is the amount of rotation an object has taking into account its mass and shape. The rate of change of angular momentum is the torque. The direction of angular momentum is given by the direction of the thumb when you curl the fingers of your right hand in the direction of the spin.
4. Angular velocity = The number of rotations made by an object about an axis per second.
5. Mass = The measure of the quantity of matter present in a body.
6. Weight = The product of the mass of an object and the gravitational acceleration acting on it. It acts vertically downwards from the centre of mass of the object
Now, to begin with, let me explain why a beyblade(or any spinning object) stays upright when spinning. But before that, let us consider the case of an object that isn't spinning.
What happens to an object when it isn't spinning:
Any object is constantly under the action of a number of forces. The first force is the object’s weight. The second is the normal reaction acting on the object by virtue of the surface on which it is kept. Apart from these two, there is also the force exerted by air particles on the object. But often the latter is so small that it barely shows any visible effect. Then there is also the force of friction which acts whenever an object is acted upon by a force in a direction perpendicular to the surface(in this case, the horizontal direction).Apart from this, there is also the torque of these forces which acts on the object. Now, if you place an object perfectly upright, the vertical forces get balanced and the horizontal forces(the force by air particles, if any) are the only ones acting. If you are to place an object perfectly upright in vacuum, it would stay upright. However, in normal conditions, there is also the force due to air particles acting which acts on the object, but it usually gets balanced by the friction.
[Image: FBD1_zpsc340b4ca.jpg]
Note that all the forces have been balanced. Hence, the object does not move(rectilinearly) in this condition. Yet, it topples. Why is that so?The answer is torque. Considering the torque about the bottom-most point(any point in general can be considered, however it is easier to calculate the torque through this point) on an object, you would observe that the radius vector between this point and the weight, normal reaction and friction is 0. Thus the torque of these 3 forces is 0 as well. However, the torque of the force due to air particles isn’t non-zero. It is this torque which is responsible for initiating the toppling and as the object turns, the torque increases because now, the radius vector of weight increases as well. Thus, the object topples and falls.
[Image: FBD2_zps6243e08f.jpg]
So, what is so special in a spinning object which lets it stay upright?:
The answer is angular momentum.When you impart spin to an object, it gets a corresponding amount of angular momentum as well. This angular momentum acts in the upward direction.
[Image: FBD3_zps81b5f74c.jpg]
Now, let us go back the non-spinning object, however, this time, we consider the angular momentum as well.The force balance is exactly the same(because spinning is not a force). And the torque balance equation as well(because angular momentum is not a torque). However, we also have angular momentum to consider this time. The direction of the torque in this case is coming outward from the plane of the paper. Now since we also have angular momentum directed upwards, the torque in this case gets utilized in changing the direction of the original angular momentum.
[Image: FBD4_zpsde6af455.jpg]
However, the torque is so small that it doesn’t produce a visible change in direction of the angular momentum. Usually, the time needed to produce a visible change is long enough to let the object run out of spin(because the value of the torque itself is quite low) and it turns into the same scenario as that of an object that isn’t spinning.Note that the angular momentum itself decreases in magnitude with the passage of time due to the resistance to motion(sort of viscous force) offered by the air particles and the frictional torque offered by the floor(when the tip isn’t perfectly sharp).However, at times, there are forces that change the direction of angular momentum a little faster and at these times, the torque due to gravity comes into picture as well. Now, this torque always acts perpendicular to the direction of angular momentum. As a result, the direction of the axis of rotation(which is same as the direction of the angular momentum) keeps changing continuously with time.
[Image: FBD5_zps5b277087.jpg]
The value of the angular momentum itself keeps decreasing as well. However, if we assume the angular momentum to be constant(ideal case), the axis of the top traces a perfect circle due to the torque that acts perpendicular to it. This phenomenon is called as precession. In reality, as the top rotates under the action of precession, the value of angular momentum decreases as well(due to friction, viscous force). As a result, the angle that the axis of rotation makes with the vertical increases(and hence, the torque of gravity rises as well) and slowly, the top topples.
Factors that affect the rotational motion of the top
1. Moment of inertia: The greater the moment of inertia, greater the ability of a top to remain spinning. Now, how do we increase the moment of inertia? First of all, the moment of inertia depends on mass and the radius. Therefore, for two similar objects with uniform weight distribution, the moment of inertia of the object with greater weight is greater(It is harder to stop a heavier body). Secondly, an outward distribution of weight results in a higher moment of inertia. As a simple example, if you take a disc and a ring of same mass and radius, it becomes easier to stop the disc than to stop the ring when they are given the same angular velocity(For those interested, the moment of inertia of a ring is twice that of a disc). Thus, for a higher spin time, a heavy top with all its weight focused outside is required. Now, coming to beyblades. Since the beyblades are already manufactured with a particular mass and weight, we cannot change the weight distribution of individual parts. However, in MFB we are able to alter the moment of inertia a little with the use of metal faces and in plastics, the same can be done with the help of weight disks. I’ll explain the exact effect of all these later in the article.
2. Shape of the surface in contact with the floor: It isn’t tough to figure out that a sharper surface that has a lesser surface area of contact with the floor gives a longer spin time. The reason? Friction. However, it isn’t exactly due to the force of friction. It is a common misunderstanding that friction depends on the area of the surface in contact. However, that is false. Friction is dependent only on the normal reaction offered by the surface. So, why do sharper tips spin longer? The reason is the ‘torque’ of friction. The torque of friction is dependent on the surface in contact. The larger the area of the surface in contact, the greater the torque of friction. Needless to say, sharper tips have the least torque of friction acting on them and the longer ones have the largest torque of friction acting on them.
3. Shape of the beyblade: It’s a fairly known fact that a round shape allows for a higher spin time. The reason being the minimal torque of air resistance offered to round objects. If the surface is smooth, the air resistance is less and if it is rough, the air resistance offered is higher. And as the air resistance rises, the torque of air resistance rises as well so the angular velocity decreases.
4. Position of centre of mass: The position of the centre of mass doesn’t come into picture until precession does. The reason is that the position of centre of mass only affects the torque of gravity. And in an upright spinning object, the torque of gravity is almost always zero, so the position of centre of mass makes almost no difference. However, once we take precession into consideration, the torque of gravity comes into the picture as well. In this case, as the position of the centre of mass shifts lower, the torque of gravity becomes lower as well and as a result, the spinning time increases. You could easily verify this by testing any combo with MB and then using MF-M(or a normal metal face) and B tip. The combo with MB will have a higher spin time.
Factors affecting the translatory motion:
1. Friction: Contrary to what most people think, friction actually aids the translatory motion of a beyblade. When you launch a beyblade with a certain velocity, it automatically comes under the action of friction, gravitational acceleration(due to slope of stadium) and centrifugal force(Centrifugal force is actually a pseudo force that comes into action if you consider a reference frame undergoing circular, not rotational, motion). Since circular motion is usually exhibited by flat tips, the friction is an influential factor in the motion of attack type beyblades. The friction is higher for rubber tips than for plastic and is the least for metal tips. Now, if the frictional force offered by the stadium is higher than the centrifugal force(which is a function of the mass and the velocity of motion,not of rotation, of the beyblade), then bravo, your beyblade stays in the stadium. If not, bad luck, it self Kos. I’ll explain the exact reason a little later while explaining tornado stalling. However, it is interesting to note that an increase in friction also means that the torque of friction rises and hence the spin time of a beyblade is drastically reduced as well.
2. Centrifugal force: As I mentioned above, it is a function of the mass of the beyblade and the velocity of the beyblade’s motion. And if it exceeds the friction offered by the tip, your beyblade self-Kos(most of the time). Reason, coming later in the article.
Coriolis Force: It is a misconception that coriolis force also affects the motion of a beyblade. The coriolis force is acting on the beyblades indeed but it is not enough to affect its motion as much as friction and centrifugal force. The coriolis force is a product of mass, angular velocity of the earth(which is a very small number) and the velocity of the beyblade in motion. The product is a very small number which is quite insignificant to be considered.
Spin stealing and moment of inertia:
From a physics perspective, spin stealing is more like the law of conservation of angular momentum wherein two beyblades in contact maintain a certain angular momentum. The angular momentum of one decreases and that of another increases and in the process there is equalization of angular velocity of the two beyblades. The cause of spin-stealing is the contact force that acts when the two beyblades come in contact. According to Newton’s third law of motion, the contact force acting on the two beyblades is equal and opposite in direction. So while it increases the angular velocity of one, it decreases the velocity of another in case of a left-spin vs right-spin battle. In case of a right-spin vs right-spin battle, the angular velocity of both the beyblades decreases simultaneously.
[Image: FBD7_zps9f077445.jpg]
It is important to note that the contact force acting on both the beyblades is equal. However, the torque of the contact force isn’t. For a beyblade having a larger radius, the torque is greater and for a beyblade having a smaller radius, the torque is smaller(this is assuming that there is MW-MW contact). However, when the radius rises, so does the moment of inertia. So, how exactly does the radius affect a beyblade during spin-stealing? Looking at the expression of moment of inertia and torque, we can conclude that the angular acceleration produced in a beyblade during spin-stealing(regardless of direction) is inversely proportional to the radius(again, this is assuming that there is MW-MW contact). Thus, a larger radius means that a beyblade would gain(or lose) spin easily. Similarly, for a smaller radius, the beyblade does not gain(or lose) spin easily. Generally, in spin-steal battles, the beyblade having the higher radius is the stamina type. Therefore, spin stealing is usually a one-directional phenomena with the spin-stealer gaining spin and the stamina type losing it. Now, if the contact is not MW-MW and the spin-stealer hits the track, the angular momentum gained by the spin-stealer isn’t much and is usually not enough to compensate the amount of angular velocity it loses due to friction. On the contrary, the stamina type doesn’t lose too much angular velocity either and hence the stamina type remains spinning for much longer. So, how do we ensure the victory of a spin-stealer? One way to do this is to prevent the beyblade from toppling over for as long as possible(i.e. increasing precessing time).
[Image: FBD8_zps8abf8b3d.jpg]
The best way to do this to use a low track and to choose a height which prevents the beyblade from toppling even when it is not spinning and hope that the opponent doesn’t create a similar combo with his stamina type or doesn’t create a combo so high that you keep hitting the track. Because spin-stealing is most effective when you use lower tracks and avoiding spin from being stolen is most effective when you use a higher track.
Effect of metal faces:
As I mentioned earlier, using a metal face alters the moment of inertia and the position of centre of mass of a beyblade. The order of moment of inertia is this way: MF-L >Normal face>Metal face >MF-H>MF-M. And the order of position of centre of mass(the first one in the list has the highest centre of mass) is this way: Metal Face>MF-L>Normal face>MF-H>MF-M. So, what does this mean in terms of beyblade? It means that when you use MF-M, the beyblade’s time period of precession rises and when you use MF-L, the moment of inertia of a beyblade rises. Note: The order I mentioned above is applicable for most MFB MWs, however, the order may change according to the MW’s weight and its distribution.
Tornado stalling, Banking and self-KO
(Note: This discussion takes into consideration the attack type beyblades)
The physics behind tornado stalling is based on the friction and normal reaction between the tornado ridge and the tip. Basically, as I mentioned earlier, to avoid a self-KO you need to have a force of friction that is higher than the centrifugal force acting on the body. As soon as you launch a beyblade, the force of friction begins acting on it. This friction, combined with the component of gravity along the slope are responsible for making the beyblade undergo circular motion. Now, when the beyblade has been launched outside the tornado ridge, it can only stay in the stadium if it has a velocity lower than a particular value(Calculation follows in the diagram for those interested).
[Image: FBD9_zpsa938b07a.jpg]
If the velocity exceeds that value, the centrifugal force dominates and the beyblade heads outside the stadium and self-Kos. Note that the velocity is a result of friction force and is also dependant on the angular velocity imparted to the beyblade. Hence, if you launch a beyblade straight and higher than a particular angular velocity, it will most likely self-KO. However, if you launch it within the tornado ridge and if it is able to grip on to the ridge, it will last inside the stadium even for a higher value of angular velocity. This is because, the normal reaction offered by the ridge also opposes the centrifugal force, and combined with the component of gravity along the slope, it can sustain a relatively higher value of centrifugal force.
[Image: FBD10_zps6da55455.jpg]
Thus, this time the beyblade stays spinning in the stadium and does not self-KO. Moreover, it usually gets a higher velocity of circular motion and an increased spinning time as well. Why does this happen? Before I explain that, let me show how friction works. First of all, when you launch a beyblade, it does not always land with its tip parallel to the stadium floor. It always ends up a little tilted. When that happens, the force of friction does not act uniformly on the beyblade. It is higher for the half that touches the stadium more. Thus, the beyblade moves in a direction given by the friction. Now, when it lands perfectly parallel to the stadium floor, ideally there is no unbalanced friction force acting on it and the only unbalanced force that acts on it is the component of gravity that is parallel to the slope of the stadium. This, in this case the beyblade moves directly towards the centre.
[Image: FBD11_zpsbbad7e6c.jpg]
However, it doesn’t stop there. As it reaches the centre, the beyblade tilts a little again and again friction acts on it in tangential(can’t find a better word) direction. Due to this, it takes a curve as it reaches the centre but as soon as it moves a little upwards, it becomes parallel to the stadium floor again and moves straight.
[Image: FBD12_zps8348ab2f.jpg]
In this process, the component of force of gravity parallel to slope of the floor starts acting on the beyblade again and it repeats the same pattern again. This is very close to the flower pattern that is generated when you bank a beyblade. If you launch it in the forward direction(catapult shoot), you also impart a horizontal velocity to the beyblade. Thus, the friction increases and the beyblade gets a little curvilinear motion when going down and going up as well. This is how the flower pattern is generated when using sliding shoot. Now, back to the tornado stalling scenario. When a beyblade’s tip grips on to the tornado ridge, it stays upright. Thus, the friction is higher on the side touching the ridge. This friction opposes the spinning motion and hence acts in the direction of the curvilinear motion of the beyblade. As a result, it provide a tangential acceleration to the beyblade and makes it circle the ridge even faster while also reducing the beyblade’s rotational angular velocity. However, the value of friction in this case is much lesser than the friction opposing the rotational motion when you launch it with the tip parallel to the floor. Thus, the beyblade’s spin time increases as well. Now, as the beyblade keeps circling the ridge, the rotational angular velocity decreases steadily but comparatively slowly. After a particular value is attained by the rotational angular velocity, the friction changes its direction and this time reduces the velocity of the beyblade. As the velocity decreases, the centrifugal force decreases as well and gradually the beyblade loses contact with the ridge and moves closer to the centre. The radius of the circle that it traces decreases as well with the decrease in centrifugal force and finally it comes to a halt at the centre(or collides with the beyblade spinning in the centre).
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)
RE: Physics - Nocto - Jan. 07, 2014
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.
RE: Physics - Justaway - Jan. 07, 2014
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.
|