This post is about the visualization of a gyroscopic phenomenon of a rotating body. MapleSim models and a description for those who do not have MapleSim are provided for their own analysis. Implementation with other tools like Maple might give further insight into the phenomenon.

With appropriate initial conditions, a ball thrown into a tube can pop out of the tube. This can be reproduced with a MapleSim model

Throwing_a_ball_into_a_tube_A.msim

To hit a perfect shot without trial and error, time reversal was applied for the model (reversed calculation results of a ball exiting the tube are used as initial conditions for the shot). This worked straight away and shows that this model is sufficiently conservative.

This phenomenon has recently attracted attention on YouTube. For example, Steve Mold demonstrates the effect and provides an intuitive explanation which he considers incomplete because the resulting vertical oscillation of the ball does not match theory and his experiments. He suspects that the assumption of a constant axis of rotation of the ball is responsible for this discrepancy.

However, he cannot demonstrate a change of the axis of rotation. In general, the visualization of the rotation axis of a ball is difficult to achieve in an experiment. On the contrary, visualization is much easier in a simulation experiment with this model:

Throwing_a_ball_into_a_tube_B.msim

The following can be observed for a trajectroy that does not exit the tube:

At the apex (the top) of the trajectory, the vector of rotation (red bold in the following images) points downwards and is essentially parallel to the axis of the cylinder. The graph to the left shows the vertical (in green) position and one horizontal position (in red). The model applies gravity in negative y direction.

On the way down, the axis of rotation points away from the direction of travel (the ball orbits counterclockwise in the top view).

At the bottom, the vector of rotation points towards the axis of the cylinder.

On the way up, the axis of rotation points in the direction of travel.

These observations confirm that the assumption of a constant axis of rotation is too simplified. Effectively the ball performs a precession movement know from gyroscopes. More specifically, the precession movement of the rotation axis rotates in the opposite direction of the rotation of the ball.

However, the knowledge and the visualization of this precession movement do not provide more insight for a better intuitive explanation of the effect. As the ball acts like a gyroscope, a second attempt is to visualize forces that perturb the motion of the ball. Besides gravity, there are contact forces exerted by the tube. The normal force at the contact as well as the gravitational force cannot generate a perturbing momentum since they point to the center of the ball. Only frictional forces at the contact can cause a perturbing momentum.

Contrary to the visualization of the axis of rotation, visualization of contact forces is not straight forward in MapleSim, because neither the contact point nor the contact forces are directly provided by components of the MapleSim library. Only for a single contact point, a work-around is possible by measuring the reactive forces on the tube and then displaying these forces in a moving reference frame at the contact point. The location and the orientation of this frame are calculated with built-in mathematical components. To illustrate the additional effort, the image below highlights in yellow the components only needed for the visualization of the above images, all other components were required to visualize the contact forces and frictional moments.

Throwing_a_ball_into_a_tube_C3.msim
It required many attempts to get to a working model. Several kinematic models for a rotating reference frame at the contact point failed. Finally, mathematical operations on kinematic signals (measured by sensors) and motion drivers were successful.  

In the following, the model is used to visualize the right-hand rule for the following vectors:

• in green the disturbing frictional moment
• in red (now with a double headed arrow) the angular velocity (for a sphere it points in the same direction as the vector of the angular momentum and the axis of rotation)
• in pink the vector of the angular velocity of the precession movement

At the top, the vector of precession indicates that the axis of rotation is diverted away from the direction of travel (i.e. pointing backwards). This is in line with the above image of the ball “on the way down”.

At the bottom, the vector of precession indicates also that the axis of rotation is diverted away from the direction of travel. This however cannot be seen in the above image of the ball “on the way up”. This discrepancy is an indication that the vector of angular velocity of the precession movement might not sufficiently predict the future orientation of the axis of rotation.

Overall, there is little symmetry in the two extreme positions at the top and at the bottom. A bending of the trajectory downwards (pitching down) at the top indicated by the vector of precession, cannot be seen at the bottom: The vector of precession does not indicate a bending of the trajectory in an upward direction.

It turns out that the right-hand rule does not provide the hoped-for better explanation either. However, the model was not a complete waste of time since it provided two unexpected and very counterintuitive observations:

• At the bottom, the speed of the balls center is the lowest. For an object descending in a gravitational field, one would expect a gain in speed. A closer look at the graph of the angular velocity (lower graph) reveals that the ball is spinning at the highest rate at the bottom. This means that potential and kinetic energy at the top are converted to rotational energy at the bottom.
• Although the ball slows down (and speeds up in angular velocity) while descending there is no frictional force component in circumferential direction. Seen from above, the ball orbits at constant velocity. Only a vertical frictional force component acts all the time. Frictional forces in circumferential direction slowing down the ball can only be seen at the beginning of the simulation when the ball slips on the tube up to the moment when it rolls without slippage.

Overall, the closer one looks, the less intuitive it gets. What makes this phenomenon so difficult to understand is the constantly changing constraint of the ball. At each time increment the location and orientation of the contact changes with respect to the direction of the (instantaneous) direction of precession. This makes the phenomenon so obscure. It might be easier to find an “intuitive” explanation for the tennis racket paradox (or intermediate axis theorem) where no external forces act.

Even with a physics background and the right-hand rule of precession at hand, it requires allot of imagination to predict the movement of the ball. This is, in my opinion, not intuitive at all for most people. After all, the premotor cortex of the human brain seems to have constant difficulties to learn precession – for sure precession prediction is not hardwired. If it was, the paradox wasn’t so perplexing, and we could imagine/predict what the golf ball does next.

In summary, this simulation experiment revealed details not known before (at least to me) about the phenomenon. The experiment did not provide more insight for a better intuitive explanation but on the contrary raised more questions. It is another case of “knowing more, but not getting smarter”.

At the very least, the simulations also show the benefits of carrying out virtual experiments under various conditions that are difficult or even impossible in an experiment. In any case, such experiments are of educational value  - not only in classical physics.

Comments on the product:

It was possible to verify results of MapleSim: The model reproduces the magic numbers sqrt(7/2) and sqrt(5/2) for the ratios of circular rotation and vertical oscillation frequencies for a full and a hollow sphere respectively. See the first model.

The (laborious) work-around presented here cannot be applied to most real-world contact problems. Visualization of the contact point, contact forces and contact slippage are therefore a desirable extension to MapleSim’s contact capabilities. I do not think that this is provided by other tools.

A surface pattern for the ball would have been helpful to better visualize the rotation of the ball.

A moving observer view (in this case an observer in the reference frame of the contact) could facilitate observation.

Further viewing:

• The physical engine of Blender was used in a video to reproduce the phenomenon qualitatively.
• There is an ”improved” intuitive explanation of Steve Mold’s explanation which uses frictional forces and provides physical background. It is not clear to me which part of the visualization is animated and which is physically simulated. At least some sequences do not make sense: The vector of the external frictional moment on the ball suddenly changes direction. The “improved” intuitive explanation also states that the rotational axis leans constantly toward the contact point. I do not see this in my simulation (the contact point is indicated with a red dot in the images above). Also, the precession vectors in my simulation did not reveal an intuitive explanation for a reduction in vertical oscillation frequency.

Further work:

• Is the vertical oscillation truly sinusoidal as the horizontals are?
• Is the point of contact always in the northern hemisphere of the ball? More general: In one hemisphere?
• In a simulation without gravity: Does the vector of precession better predict the trajectory?
• ...
   

The complete Maple Conference 2024 program is now available online. You can view it HERE.
Thank you to all those who voted for the "Audience Choice" sessions. The winning topics are listed in the program.

Registration is still open and free of charge.  

We hope to see you there!

Hello,

Below I am attaching a Maple worksheet on rolling a circle on a flat curve and generating a cycloidal curve.

Regards!

Cycloidal_curve.mw



 

This is a task from one forum:  “Let's mark an arbitrary point on the circle. Let's draw a segment from this point, perpendicular to the diameter, and draw a circle, the center of which is at this point, and the radius is equal to this segment. Let's mark the intersection point of the segment connecting the intersection points of the circles with the perpendicular segment. Prove that the locus of all such points is an ellipse.”
I wanted to get a picture of a numerically animated "proof" using Maple tools.
МАTH_HЕLP_PLANET.mw
 And in fact, it turned out that AB=2AC, or AC=BC.

In this post, I would like to share some exercises that I recently taught to an undergraduate student using Maple. These exercises aimed to deepen their understanding of mathematical concepts through computational exploration and visualization. With its powerful symbolic computation capabilities, Maple proved to be an excellent tool for this purpose. Below, I present a few of the exercises and the insights they provided. Interestingly, the student found Maple to be more user-friendly and efficient compared to the software he usually uses for his studies. Below, I present a few of the exercises and the insights they provided.

One of the first topics we tackled was the Fourier series. We used Maple to illustrate how the Fourier series approximates a given function as more terms are added. We explored this through both static plots and interactive animations.

To help the student understand the behavior of different types of functions, we defined piecewise functions using Maple's piecewise command. This allowed us to model functions that behave differently over various intervals, such as the following cubic function exercise

Maple's Explore command was an effective tool for creating an interactive learning environment. We used it to create sliders that allowed the student to vary parameters, such as the number of terms in a Fourier series, and see the immediate impact on the plot.

Download Fourier_Series.mw

This is another attempt to tell about one way to solve the problem of inverse kinematics of a manipulator.  
We have a flat three-link manipulator. Its movement is determined by changing three angles - these are three control parameters. 1. the first link rotates around the black fixed point, 2. the second link rotates around the extreme movable point of the first link, 3. the third link − around the last point of the second link. These movable points are red. (The order of the links is from thick to thin.) The working point is green. For example, we need it to move along a circle. But the manipulator has one extra mobility (degree of freedom), that is, the problem has an infinite number of solutions. We have the ability to remove this extra degree of freedom mathematically. And this can also be done in an infinite number of ways.
Let us give two examples where the same manipulator performs the same movement of the working point in different ways. In one case the last red point moves in a straight line, and in the other case it moves in an ellipse. The result is the same. In the corresponding program texts, the manipulator model is described by a system of nonlinear equations f1, f2, f3, f4, f5 relative to the coordinates of the ends of the links (very easy to understand). The specific additional connection that takes away one degree of freedom is highlighted in blue. Equation of a circle in red color.
1.mw

2.mw


And as an elective. The same circle was obtained using a spatial 3-link manipulator with 5 degrees of freedom. In the last text, blue and red colors perform the same functions as in the previous texts.
3.mw

 

Circles inscribed between curves can be specified by a system of equations relative to the coordinates of the center of the circle and the coordinates of the tangent points. Such a system can have 5 or 6 equations and 6 variables, which are mentioned above.
In the case of 5 equations, we can immediately obtain an infinite set of solutions by selecting the ones we need from it. 
(See the attached text for more details.)
The 1st equation is responsible for the belonging of the point of tangency to one of the curves.
The 2nd equation is responsible for the belonging of the point of tangency to another curve.
In the 3rd equation, the points of tangency on the curves belong to the inscribed circle.
In the 4th and 5th equations, the condition is satisfied that the tangents to the curves are perpendicular to the radii of the circle at the points of contact.
The 6th equation serves either to find a specific inscribed circle or to find an infinite set of solutions. It is selected based on the type of curves and their mutual arrangement.

In this example, we search for a subset of the solution set using the Draghilev method by solving the first five equations of the system: we inscribe circles in two "angles" formed by the intersection of the exponent and the ellipse.
The text of this example, its solution in the form of a picture,"big" option and pictures of similar examples.
INSCRIBED_CIRCLES.mw


 

Addition 09/01/24, 
One curve for the first two equations in coordinates x1,x2 and x3,x4
f1:= x1^2 - 2.5*x1*x2 + 3*x2^2 - 1;
f2:= x3^2 - 2.5*x3*x4 + 3*x4^2 - 1;

As AI becomes increasingly relevant in the tech world, Maplesoft has taken steps to integrate AI into our products. We recently launched two new features: Ask AI in Maple Learn and Word Problem Solver in Maple Calculator. 

Ask AI - Maple Learn

As a Math Content Creator at Maplesoft, sometimes I find myself in a creative rut. What documents would be engaging for students? How can I address certain math topics in a fun and interactive way?

I've had the pleasure of creating several collections during my time, including Extreme Value Theorem, Intermediate Value Theorem, and Polynomial Long Division. Nonetheless, each collection took a lot of storyboarding and creativity before I even began drafting them, and I've missed out on creating so many more collections because of this long idea generation process. Having a tool in my back pocket to reignite those creative juices would make it so much easier and faster to create new and exciting Maple Learn documents. 

Luckily, our new Ask AI feature in Maple Learn can help with that! 

Whenever you enter text into a Maple Learn document, a new Context Panel operation called "Ask AI" will pop up. Simply click that button to receive an AI response related to your prompt.

One of my favourite uses of Ask AI is to pick a random subject or phrase and see what the AI responds with. The Ask AI feature is designed to respond with a mathematics-centric answer so it will twist even the least mathematical of concepts into a math problem! The prompt "tacos" resulted in some formulas about sharing tacos with friends, and a prompt of "celebrity gossip" introduced statistical functions to compute the number of celebrity mentions per day. 

I also found that completing part of a tongue twister will result in some funny AI responses!

Here are a couple of my favorites below:

"She sells sea shells..."

Ask AI completes this tongue twister, then offers some formulas to compute the profit of selling S shells!

"How much wood..."

After relating that this tongue twister is not a mathematical problem, Ask AI then builds a simple formula for computing how much wood a woodchuck would (hypothetically) chuck.

There are many more applications of this feature, and I hope you all enjoy exploring them as you create documents on Maple Learn. If you're having trouble inputting text into your documents, or looking for a quick introduction to Maple Learn, check out the Walkthrough Tutorial. Beginner Tutorial (slide 8) addresses adding text to your document. Check out this blog post if you aren't sure how to access the Walkthrough Tutorial. 

Word Problem Solver - Maple Calculator

Maple Calculator now offers support for word problems by leveraging AI. Simply take a picture of your word problem and Maple Calculator will provide a solution generated by AI.

Here is a quick example:

I wrote on paper, “Alice and Bob have 17 apples total. Alice has double the number of apples as Bob plus two. How many apples does Bob have?”. Then I took a picture of this in Maple Calculator, and it gave me a breakdown of the problem using linear equations. See screenshots of my Maple Calculator below.

AI can be an amazing tool, but it can also make mistakes. We ensure that all our tools that incorporate AI clearly indicate its use, so that our users can know when AI is used and choose whether to use it. We're committed to remaining transparent about AI as our journey continues and we are always open to feedback. 

For our community of educators, a valuable exercise for students might be to show examples where AI makes mistakes and encourage students to find and explain the errors.

As an example, here is an algebra problem answered by Ask AI in Maple Learn – but it made a mistake! See if your students can spot where it went wrong and explain what should happen instead.

Building these skills will translate into good critical thinking skills that will benefit students inside and outside the classroom. For example, these exercises aim to help students identify their own mistakes in math and critically evaluate online sources. We would love to hear feedback about these exercises if you try them.

We hope these features will come in handy next time you use Maple Learn and Maple Calculator! 

I’m thrilled to introduce the updated Q&A Cards Creator! Michael Barnett had created the original Flash Cards Creator, inspired by the quiz creators in the Maple Learn gallery. I added some of the features (mentioned later in this post) that will help you use this tool to make more comprehensive quizzes. Students can use the creator to quiz themselves before a test, and instructors can integrate more practice quizzes into their lesson plans. One feature I particularly love is the ability to link full solutions to the back of each card, allowing users to understand the answers in depth (as shown in this document). Additionally, you can link a general solutions package (as seen here) if individual solutions aren’t necessary for each question. Below is an example of what the Q&A cards can look like from the users point of view.
This creator is a great example of the Maple Learn documents you can create through scripting in Maple. With a single script, you can create an infinite amount of content and quizzes. If you are interested in Maple scripting, here is a link to the Q&A cards script. If this script looks intimidating, feel free to check out this blog post on the basics of Maple scripting!


If you are interested in creating your own Q&A quiz, you can go to this document to get started. If you get stuck at any point creating your card set, check out the instructions included in the document for clarification. We hope you enjoy creating some quizzes with this document!

Download predator_prey2.mw

We are pleased to announce that the registration for the Maple Conference 2024 is now open.

Like the last few years, this year’s conference will be a free virtual event. Please visit the conference page for more information on how to register.

This year we are offering a number of new sessions, including more product training options and an Audience Choice session.
You can find an overview of the program on the Sessions page. Those who register before September 10th, 2024 will have a chance to vote for the topics they want to learn more about during the Audience Choice session.

We hope to see you there!

Maple Learn has so much to offer, but it can be tricky to know where to start! Even for those experienced with Maple Learn, sometimes, we miss an update with new features or fall out of practice with older ones. Luckily, we have the perfect solution for you–and it shows up right when you open your first document.

Introducing our brand-new Walkthrough Tutorial!

The tutorial covers all the main features of Maple Learn: from assigning functions, to using the Plot commands and Context Panel operations, all the way to creating your own visualizations with the Geometry commands. Stuck? Hints are provided throughout, or just click "Next" and the step will be completed automatically. 

If you're just starting out with Maple Learn, try the Beginner tutorial and work up to Advanced. This will introduce you to a holistic view of Maple Learn's capabilities along with some Maple Learn terminology. If you have some experience, starting with the Beginner tutorial is still a great option, but you may wish to begin with the Intermediate and Advanced tutorials. The Intermediate and Advanced sections cover how to use newer features of Maple Learn and you might discover something you haven't seen before!

How do I access the tutorial?

The tutorial will automatically launch when you open a new document. Head to https://learn.maplesoft.com and click "Open new document".

If the tutorial doesn't open automatically, it may have been disabled. You can manually open it by clicking the "Help" button in the top right, then clicking "Walkthrough Tutorial". 

There you have it! I had been using Maple Learn for the past few months and only recently discovered these two incredible features:

Silencing Groups (Intermediate - 6/7)

Live Sessions (Advanced - 6/6)

I found these features thanks to the Walkthrough Tutorial and my experience on Maple Learn hasn't been the same since! The Walkthrough Tutorial is a great introduction for new users, and a quick refresher for experts, but isn't the end of exploring Maple Learn's capabilities. See our How to Use Maple Learn (maplesoft.com) collection and our Getting Started with Maple Learn (youtube.com) video for more. You can also challenge The Treasure of Maple Learn (maplesoft.com) – a collection of documents designed to gamify exploring Maple Learn's features. Check out our blog post on The Case of the Mysterious Treasure - MaplePrimes to learn more about this collection. 

Hope you enjoy our new tutorial and let us know what you think!

This is a reminder that presentation applications for the Maple Conference are due July 17, 2024.

The conference is a a free virtual event and will be held on October 24 and 25, 2024.

We are inviting submissions of presentation proposals on a range of topics related to Maple, including Maple in education, algorithms and software, and applications. We also encourage submission of proposals related to Maple Learn. You can find more information about the themes of the conference and how to submit a presentation proposal at the Call for Participation page.

I encourage all of you here in the Maple Primes community to consider joining us for this event, whether as a presenter or an attendee!

Kaska Kowalska
Contributed Program Co-Chair

The Proceedings of the Maple Conference 2023 is now out, at

mapletransactions.org

The presentations these are based on (and more) can be found at https://www.maplesoft.com/mapleconference/2023/full-program.aspx#schedule .

There are several math research papers using Maple, an application paper by an undergraduate student, an engineering application paper, and an interesting geometry teaching paper.

Please have a look, and don't forget to register for the Maple Conference 2024.

A simple visual way to show that the parametric equation of a circle is a helix in our three-dimensional space.
Parametric equation of a circle f1 and f2.
The helix is ​​defined by the intersection of two mutually perpendicular cylindrical surfaces f1 and f2.

 

restart; with(plots): 
R := 1.;
f1 := x1-R*cos(x3); 
f2 := x2-R*sin(x3); 
PT := implicitplot3d([f1, f2], x1 = -6 .. 6, x2 = -6 .. 6, x3 = -2 .. 12, numpoints = 10000, style = surface, color = [blue, green], transparency = .5):
IT := intersectplot(f1, f2, x1 = -1 .. 1, x2 = -1 .. 1, x3 = -2 .. 12, thickness = 3, axes = normal, grid = [10, 10, 30]): 
display(PT, view = [-6 .. 6, -6 .. 6, -2 .. 12]);
display(PT, IT, view = [-6 .. 6, -6 .. 6, -2 .. 12]); 
display(IT, view = [-R .. R, -R .. R, -2 .. 12], scaling = constrained)