Physics of Figure Skating-please help!

[xofivebyfive]

I got terrific responses 3 or 4 years ago freshman year when I needed information about the Geometry of skating. well, now I have a project for physics and I need info about the physics involved in skating. any ideas?

here are the things I need to include(it was designed for rollercoasters but I'm doing it on skating since I didn't go on the Six Flags trip):

Kinematics
a. Can you use your knowledge of kinematics to analyze the motion of the ride?
b. Accelerations and Velocities

Forces
a. Force diagram

b. Static forces
i. things that hold the ride up?

c. Dynamic fordces
i. forces that move the ride
ii. force the ride exerts on you
iii. what work is done?

d. Circular motion
i. What forces contribute to the centripital force?
ii. What are the accelerations that result?
ii. What holds you into the path?

And I have to pick two of the major topics from these(energy, harmonic motion, electricity and magnetism):

Energy
a. Where does the energy for the ride come from?
b. How does the energy get used(to move the ride)?
c. Where does the left over energy go?

Harmonic Motion(Waves)
a. Is the motion repetitive?
b. What is the frequency?

Electricity and Magnetism
a. What kind of motor is involved?
b. How much power does it take to run the ride?
c. What is the voltage and current?
d. What is the bill

I mostly can't find information about force.. anybody know any information or websites that talk about force, because I can't find any!!

so um.. I have no idea how to convert those questions to pertain to figure skating... uhhh. any ideas guys? thanks so much if you can help me. I've been SO sick(with Lyme blah blah blah :D) and am DROWNING in makeup work and this is due Friday so.. HELP?? thank you!

[Bill_S]

Any good college textbook on dynamics will help you understand force diagrams, kinetic vs. potential energy, etc. It's been nearly 40 years since I studied that in college, so I can't remember the text I used. (It probably wouldn't be in print anyway!)

A physics prof here recently assembled a presentation concerning how blades glide across a solid surface with little friction, plus did some calculations about some figure skating moves. It's a Power Point presentation and I have a copy of it here (sans videos), but it's not mine to give, unfortunately.

[PhysicistOnIce]

Here are a few things that come to mind immediately that you may be able to use.

Edges: these are an example of circular motion (our edges should take us around a curve). You could take a look at the angle of the edge of the blade in the ice and where the weight of the skater is and see how this creates a centripetal force.

This is where you could easily have a nice force diagram showing the weight, reaction force from the ice and a net force that includes a centripetal component.

Angular momentum: spins and jumps are a great example of this, take a look at someone entering a spin with their arms and legs out and then as these are drawn in to the body the angular velocity increases. It is perhaps a little harder to see when not slowed down, but you can see the same physics in a multi-rotational jump.

If you need more stuff on forces it might be worth considering looking at a dance or pairs lift as now you have two bodies (literally in this case!) to study.

For the part about where the Energy comes from, it could be useful to look at how knee bend and shifting weight can provide a source of energy (think about potential energy here) in addition to the obvious aspect of pushing one foot (or toepick in my case!) against the ice.

This may be a little tenuous depending on what is required for your assignment, but if you need to study some sort of simple harmonic motion, then you could look at what is involved in power-pulls (one foot slalom).

[fsk8r]

I'm struggling with your pick 2 from 3. I figure Energy is a no brainer for the skating side of things, but I'm struggling with harmonic motion or electricity and magentism. i don't think you really can start explaining the magnetic effect of when there are 5 people on the ice, the other 4 will get in your way! So i'm eliminating electricity as irrelevant unless you want to talk about how an ice rink refrigerates the ice or the zamboni, but equally I can't see how you can do anything on harmonic motion because there aren't really any waves on a rink.
But I agree that you should be able to find something on the web about the forces.
Let us know what you come up with, I'd be interested to hear about it, but it's been over 10 years since I had to do mechanics so I'd struggle with the equations.

[Bill_S]

I just remembered that I put up a web page with some applicable dynamics notes a few years back. See if this helps any...

http://oak.cats.ohiou.edu/~schneidw/skating/skating_forces.html

[1lutz2klutz]

Also look further back on this thread for the slow motion 3-axel video that was posted by AgnesNitt ( a link to a youtube video). It might help you visualize the forces.

[xofivebyfive]

thank you thank you thank you! you guys rock! i've found some information on my own and will also use what you guys have said for most of it!

thanks!

[Sessy]

Kinematics
a. Can you use your knowledge of kinematics to analyze the motion of the ride?
b. Accelerations and Velocities


---------->
Break this down into spirals (negative acceleration due to air resistance and possibly ice friction?), braking (negative acceleration due to ice friction) and the "in 15 crossover steps from the centre of the ice rink accelerating" moves in the field exercise for the positive acceleration.

b. Static forces
i. things that hold the ride up?

-------->
Gravity and the vector opposite to gravity (so you don't get pulled through the ice) which are provided by ice upon your blades, blades upon your boots, boots upon your feet.

c. Dynamic fordces
i. forces that move the ride
ii. force the ride exerts on you
iii. what work is done?

d. Circular motion
i. What forces contribute to the centripital force?
ii. What are the accelerations that result?
ii. What holds you into the path?

------------>
Muscular power exerts horizontal (speed) and take-off (jumps) vectors that vary per jump and take-off. Gravity makes you come down again. Muscular movements transform the spinning force of an edge into the much faster spinning force in the air (pull in), then back into an edge (check out). Centrifugal forces are involved.

Skating exerts gravitational forces on you, in both spirals (takes muscle power to hold that leg up!) and jumps (especially falls, lol), but also centrifugal forces that can even push the blood into your hands if you're like, really, really good - or so I've heard.
Also I think spinning dizzyness has to do with the fluid in the brain moving or something - you may wanna look that up on google.



And I have to pick two of the major topics from these(energy, harmonic motion, electricity and magnetism):

Energy
a. Where does the energy for the ride come from?
b. How does the energy get used(to move the ride)?
c. Where does the left over energy go?

Harmonic Motion(Waves)
a. Is the motion repetitive?
b. What is the frequency?

Electricity and Magnetism
a. What kind of motor is involved?
b. How much power does it take to run the ride?
c. What is the voltage and current?
d. What is the bill

--------->
You can talk about
1. Energy comes from your muscle power (measured in joules) which comes from your food (measured in kilocalories, which can be transformed into kiljoules, a 1000 joules), how it gets used is basically to propel forward and then change the forward vector by technique into up-and-forward, up-and-backward, and centrifugal (centripedal I believe you used?) forces.

2. No idea how to use that

3. You can talk about the power it takes to create ice. You can talk about electricity generation at the powerplant that moves electromagnets (usually by steam heated either by burning gasses or nuclear fission, and the phases in electricity have to do with the magnets in a very direct way - google it) that create a phased electro-current, then gets taken to the rink.
There with the use of cooler fluids that condensate and evaporate at temperatures that differ from water, using the massive amounts of energy evaporation of these fluids takes, the water is cooled to ice (the same energy it takes to evaporate then is released as the coolants re-condense, which is why many ice rinks over here use the residual heat to heat the water in a swimming pool that's usually built right next to it) --> at least I think this is how it goes, you should check it.

You may want to go to the rink management and get numbers on their voltage, transformators they're using (probably need higher voltage than the 230 on the electrical wires, or whatever your voltage is in the USA) and annual electricity consumptions, then draw up an efficiency diagram of how much of that power is wasted --> usually a lot. You'll have to google around a bit about skating rink systems, there's several different kinds as far as I know. I hope you can get some numbers from an actual rink (maybe phone and email around to other rinks too, explaining you need it for a science project), because then you can puzzle out what the equations are exactly. If you can't, see if you can google for any government or other documents out on the internet that specify plans to build a skating rink. Often those contain estimates of how much something like that would cost. I once found such in Dutch at any rate (I didn't save them and I don't recall what I googled exactly at the time) so I'm hoping you can too.

Don't forget the energy used by the zamboni's or something, and do it for the electrical-powered version of ice sweepers (unless you're masochistic or overzealous, then you might wanna explain combustion engines and the organic chemistry of fossil fuels too - I dunno, do they even make diesel powered zamboni's? I think they do) If you really wanna go out of your way and suck up/go for the bonus points that'll give you that perfect mark, you can also ask the rink for their water consumption and then guesstimate how much energy the pressurizing of the water in the water pipes as well as the winning of this water from raw nature water took. Google is gonna be your best friend on that as well, fortunately, there's bound to be a lot of information about how water is delivered to the homes out there. It's one of those things kids always wanna know.


Hope this helps. If you've any questions left, ask away.
Plenty of skating geeks around as you can see. (Heck, don't we even have one around that built her own internet antenna and a skating rink, as well as a particle accelerator or something from a tv tube?)

For what it's worth, it sounds like a fun project. Almost makes me feel sorry I'm not in school anymore, lol.

[kayskate]

There was an educational video put out by ESPN (I think) that I used to use in my classroom. It included actual formulae about the physics of spins (centripetal acceleration). If I find more info, I will post it. otherwise, you might be able to google it.

Kay

[Query]

I think you are taking on something pretty challenging for someone who it sounds like doesn't know much basic physics.

Electrical costs vary by rink and location. (E.g., one rink might use twice as much electricity as another in the same climate, simply because of how well the building was designed, whether they keep the compressors in good shape, and whether they leave the lights on (which affects both lighting costs, and compressor usage). Apparently some types of lights are cheaper to leave on all the time - something about Mercury vapor lighting I don't understand. But any lighting creates heat, which increases compressor load.

The forces involved in skating are very complex. And the way skates work with the ice isn't agreed on - physicists aren't even sure the ice completely melts, or whether it does so because of pressure, heat, sheer, or whatever. Some people claim there is sometimes a little steam too.

There isn't complete agreement on how you get a sideways push from the blade. For example, is it the edge of the blade that pushes, or the inside curve of the hollow, or both?

A lot of people do talk about how you spin faster when you bring in your arms and legs in towards the center axis. That makes sense if you read about something called the "moment of inertia". But so many people talk about it, it is old hat.

Why are you more stable balanced on one foot if you are gliding? I have no idea. Is it because you are cutting through the ice? Does it have something to do with the motion of the water, assuming the ice truly melts? But it sure seems a dominant factor.

Very challenging for a physics beginner: You could talk about how vertical changes with motion. For example, when people talk about vertical, it usually refers to the sum of gravity (towards the center of the earth), and centrifugal force from the fact that the earth spins. But when you are skating along an arc, you also have the centrifugal force from skating that arc, which shifts the position of vertical. And if you want to get complicated, you have coriolis forces. All these change the optimal lean of your body.

How about energy in your body? Try skating several different ways. Say, push directly back, 45 degrees back, sideways, forwards. Which is most efficient, in terms of speed, how tired you feel, how long you can skate fast? How does skating effect how hungry you are, how much you need to eat to feel good. Does your weight go up or down after days you have skated? Is it the same for everyone? Do different skaters and coaches have very different ways of skating fast efficiently (yes)?

[fractals]

There is an MIT online physics video by Prof. Walter Lewin that demonstrates of conservation of angular momentum.
It is part of the BLOSSOMS project that is making educational videos for high school students.

http://blossoms.mit.edu/video/lewin.html

[Sessy]

I think you are taking on something pretty challenging for someone who it sounds like doesn't know much basic physics.

Electrical costs vary by rink and location. (E.g., one rink might use twice as much electricity as another in the same climate, simply because of how well the building was designed, whether they keep the compressors in good shape, and whether they leave the lights on (which affects both lighting costs, and compressor usage). Apparently some types of lights are cheaper to leave on all the time - something about Mercury vapor lighting I don't understand. But any lighting creates heat, which increases compressor load.

So THAT's why they always have the lights full on during the (relatively) empty day public skates and trainings, but almost fully cut the lights out during busy nighttime public skates at the Tilburg rink!!! :lol: I can't believe I just now realise it. :frus:

BTW, the questions you're asking - one could write a thesis on that. Oh wait, I think Mishin actually did (Plushenko's and Yagudin's coach). I don't think they expect quite that much detail from a high school project.

[Bill_S]

Lights contribute to the heat that must be removed from the building, but even more significant is the heat generated by a skater.

A person walking 2.2 mph on flat ground burns 3.33 kcal/min, of which 80% must be lost as heat. (ref: http://www.rwc.uc.edu/koehler/biophys/8d.html)

Using an online conversion calculator, I see that this is equivalent to 186 watts. If you have a rink with 50-100 people on it, that's a LOT of heat to remove.

[Query]

So THAT's why they always have the lights full on during the (relatively) empty day public skates and trainings, but almost fully cut the lights out during busy nighttime public skates at the Tilburg rink!!! :lol: I can't believe I just now realise it. :frus:

BTW, the questions you're asking - one could write a thesis on that. Oh wait, I think Mishin actually did (Plushenko's and Yagudin's coach). I don't think they expect quite that much detail from a high school project.

I'm not sure rinks always work out the economic details. For example, some here don't count the costs incurred when the ice is not in use when deciding whether or not to run non-busy sessions. And some rinks feel that lighting maintenance issues are more important than electrical efficiency. Frequent turn-off and on cycles make some types of bulb burn out faster. And some types of lighting are inefficient, but the bulbs are easier to change from the floor or ice. It's all too complicated.

But do you have a link or reference to Mishin's paper?

Bill_S, you are certainly right - people create a lot of energy and mositure too, which compressors and dehumidfiers have to remove. It took a real engineer (not me) to think of that. Several rinks around here also use electrical heaters to heat the air above the ice, which can't help.

Maybe a student could interview the facilities managers, electricians and maintenance staff of several rinks, to find out their very different approaches to energy and other cost usage issues. They couldn't really definitively determine who was "right", but it would be interesting. I'd love to see the results. But that might not be "physics of skating".

[Sessy]

I read in several articles that Mishin wrote a thesis (not a paper, a thesis - like, he got his diploma that way) on some sort of dynamics or kinetics or something. But those articles were in Russian and they were published around the 2006 olympics. I tried locating the thesis then, but he wrote it like back in the '70s and it hasn't been digitalised.

[Query]

For those looking at the physics of skating, here is something interesting from the USFSA, called

Biomechanics I:
Principles of Movement


http://www.usfigureskating.org/Content/BiomechanicsI-Principles%20of%20Movement.pdf