Re: Tread Mills
On Thu, 7 Nov 2002 23:31:46 -0600, yoopers
<yoopers.dsb4z@timelimit.unicyclist.com> wrote:
>harper wrote:
>2 Pi or 6.2832…
>You receive a good grade for your efforts.
>
>Teacher
Yeah a good grade but not a perfect one. In the Dutch system it might
be a 10-. 2 Pi would be 6.2831… (although rounded to four decimal
places it is 6.2832).
Klaas - overly precise headmaster - Bil
All my posts are made with 100% recycled electrons.
Re: Re: Tread Mills
The Dutch system has often come up short in more ways than one.
The link in the “heard a funny line” thread states:
Interesting.
Steve De Koekjekoekje
Re: Tread Mills
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hbaker1@pipeline.com wrote:
>You are correct. However, if you’re at the gym, try running on
>the treadmill with it tilted up for a while – it takes a lot more
>energy. So there’s more to it than simple potential energy.
I said that potential energy change is the major aspect of climbing a
hill. It is clearly not the only aspect. However, …
When running “up” the incline of a treadmill, one must lift up one’s
feet a few more inches than on level ground. That is the extra
difficulty of running on the treadmill in an inclined position.
The incline doesn’t have near the same effect on a unicycle, since the
wheel doesn’t go up and down as running feet must. When using the
unicycle, the incline simply changes the point of contact of the tire
with the treadmill which only affects balance slightly.
>On Thu, 7 Nov 2002 21:43:56 -0600, Ken Fuchs <kfuchs@winternet.com>
>wrote:
>[color=darkred]
>>>The treadmills I’ve seen at various exercise rooms have
>>>a mechanism that lifts up the front of the beast so you
>>>walk ‘up an incline’. It looks like you can get upwards of
>>>a 10-15% grade.
>>
>>A treadmill can’t completely simulate a hill, since its altitude remains
>>constant in typical use. (We assume the treadmill itself is stationary,
>>i.e. not on a truck climbing a hill.) As a result of the treadmill’s
>>constant altitude, the riders potential energy doesn’t change. The
>>increase in potential energy is the most important aspect of climbing a
>>hill. The resistance to the increase in potential energy is what makes
>>hill climbing a challenge. That challenge is missing from an inclined
>>treadmill.
>>
>>However, a treadmill is still a viable way to ride long distances in
>>one’s house.
>>
>>Sincerely,
>>
>>Ken Fuchs <kfuchs@winternet.com>
>___________________________________________________________________________
>rec.sport.unicycling mailing list - www.unicycling.org/mailman/listinfo/rsu
>[/color]
Re: Tread Mills
> >You are correct. However, if you’re at the gym, try running on
> >the treadmill with it tilted up for a while – it takes a lot more
> >energy. So there’s more to it than simple potential energy.
>
> I said that potential energy change is the major aspect of climbing a
> hill. It is clearly not the only aspect. However, …
>
> When running “up” the incline of a treadmill, one must lift up one’s
> feet a few more inches than on level ground. That is the extra
> difficulty of running on the treadmill in an inclined position.
So running with high knees would be just as easy on a 15% incline as on a
level treadmill?! Hmm…
Re: Re: Tread Mills
I don’t see why not, actually… the hard bit about going up hills normally is gaining potential energy by going upwards. On a treadmill you’re not going upwards, so you don’t need to fight against gravity quite so much.
Phil, just me
Re: Tread Mills
On Fri, 8 Nov 2002 21:19:21 -0600, UniBrier
<UniBrier.dtzsa@timelimit.unicyclist.com> wrote:
>> The Dutch settlers, for instance, gave American English cookie from
>> the word koekje, meaning a small cake.
>
>Interesting.
>
>Steve De Koekjekoekje
>
>
>–
>UniBrier - Unicyclists DeKoekkoek
You might be interested to know, then, that koekkoek (more often
spelled koekoek) is Dutch for cuckoo. Those birds speak Dutch too, as
their call is “koekoek”. 
Klaas Bil
All my posts are made with 100% recycled electrons.
Thanks for the confirmation, what’s interesting is although I am only 1 1/2 generation American, my mother emigrated from from Andijk and my paternal grandfather emigrated from Hillegom (excuse my spelling if I missed any of these), the koek=cake was brough up often when I was young. However, whenever I run accross a Netherlander they always make the cuckoo connection.
I’d rather be cuckoo than a double layer cake.
It is a pleaseure to make your acquaintance, my Uncle Clarence went by Klaas.
Treadmills
Something seems to be missing here. Just how does potential energy increase with altitude while climbing a hill? The unicycle isn’t falling. If it does fall, it’s just going to fall over, and then the potential energy becomes zero; at any given point on the hill. Get back on after an uphill UPD, and it isn’t more difficult to ride because you’re higher, but because you’ve lost your momentum.
How would placing the treadmill on a truck climbing the hill affect the potential energy of the unicyclist?
Are you saying that a truck climbing a hill will consume more fuel or need a bigger engine at a higher altitude than at a lower altitude on the same grade? On the same grade, at any given altitude, won’t the same parking brake keep the truck stationary? Doesn’t the potential energy come from gravity, which is constant regardless of altitude? Inquiring minds want to know.
Assuming a dead start (with no momentum), it’s no more difficult at sea level than it is at 1000 feet above sea level to climb an identical grade (assuming you didn’t start at sea level and are extremely exhausted).
When climbing a hill, the unicycle’s position relative to the hill’s surface is also a constant. The unicycle can’t know how far it will fall if the rider stops pedaling, so I don’t see how the potential energy is a factor in the difficulty of climbing. Muscular fatigue is the challenging factor in hill climbing. You “only” have to overcome gravity… for as long as you want to keep ascending, and maintain enough friction to avoid sliding down the hill (which is why it’s equally difficult to ride up an infinite grade at any altitude).
Re: Treadmills
U=mgh
where U=potential energy, m=mass, g=acceleration due to gravity, and h=height.
Treadmills
…but isn’t that the acceleration of a falling body?
Re: Treadmills
Potential energy is the amount of energy available to propel you into the ground if the hill suddenly dissappeared. If you fall 2000 feet you’re going to hit the ground faster than if you fell 2 feet; the extra speed has to come from somewhere, and it’d be because you had more potential energy.
It doesn’t affect the force on you at any one instant.
If you “only” overcome gravity then your altitude is not changing at all. If you want to go up you’ve got to overcome gravity, and then some, to result in a net upwards force.
Phil, just me
Oh, please don’t let the hill suddenly disappear from beneath my wheel! Oh, please oh please oh please! 
So, then, jumping UP isn’t overcoming gravity? At least until you reach apogee?
Is your potential gravity higher on the tenth step than it was on the second step
(assuming the steps don’t suddenly collapse beneath me! ) ?
As usual, it takes someone who’s just finished A level physics to put you all right. Riding on a treadmill will be as dificult as a hill (although without bumps, gradient variations, people standing in your way saying "you’ve lost a wheel, etc) because while you don’t actually gain any potential energy, if you didn’t ride you would end up going downhill with the treadmill. The work that you would be doing to increase your potential energy / altitude is instead done against the motor of the treadmill (assuming we’re talking about a powered treadmill here. If not, I’m probably talking gibberish.)
I’m not sure potential gravity exists. It might descibe gravity in the unlikely but possible eventuallity that a planet suddenly appears near you. Ahh, that’s where all those hills have been dissapearing to. However, your potential energy will increase as you go up each step, so that on the top step your peotential energy will be higher. It makes sense: think of doing a drop of the side of the steps. If you dropped halfway up, you don’t hit the ground too hard, because only a little potential energy has been converted into kinetic energy. If you drop from the top, twice the amount of potential energy is converted into kinetic energy, so you hit the ground with twice as much kinetic energy, you hit the ground harder).
Right, I think I’ve said enough to confuse evryone, including me, so I’ll stop now.
Incidentally, kinetic energy is proportional to velocity squared, so twice as much kinetic energy doesn’t mean twice the speed, before someone says something.
Treadmills
Will somebody just tilt their treadmill and ride for 10 minutes on it and tell us how it felt? Sal?
Potential is all about “IF”… If the hill vanishes… If I jump off the top step… If I ride my uni out the open bay of a C-130 at 20,000 feet… (Wishful thinkers, note: I will have my chute on!)
IF (that word again!) you’re riding up an incline, and your forward speed is equal to the speed the incline’s surface is moving in the opposite direction (as on a tilted, motorized treadmill), you have to keep going as fast as the surface in order to not stay in the same place on the treadmill’s belt, which would pull you down (or back if the treadmill were horizontal), but it would still feel as if you were climbing; not because of any gain in potential energy, but because there’s more friction between the tire and the belt of the treadmill than if the surface were horizontal and because there’s a higher place on the incline in front of your wheel. You won’t make any vertical progress as long as your speed matches the belt’s speed, but you’re still simulating moving up an incline.
Whether your treadmill’s in the basement or in the attic makes no difference… until the floor discovers its potential to disappear.
Man o man, where has this thread gone. I did try riding with the incline and it did feel like riding uphill, not a very steep hill but a hill none the less.
I’ve been pondering this question all weekend, and my guess is that they are equally difficult. It’s all about refrence points.
Potential energy by itself, doesn’t tell you anything. It’s the difference in potential energy that determines the amount of work needed.
Ok, look at it like this. If you are riding up a very wide smooth angled (45 degrees, say) slope at a constant velocity(say 5mph), then you are raising your potential energy. (using the bottom of the hill as a reference point)
Now, say the entire hill is a treadmill and it is moving at the same speed (5mph). If you ride at 5 mph, then from afar, you look like your not moving. Now, if we set our refrence point at the “bottom of the hill”, like the previous example, this point moves. Our refrence point is now moving (because the hill is moving) and we are not. [from a casual observer’s point of view] Thereby increasing our potential energy by the same amount as before.
There is no difference in potential energy that I can see. One just needs to make sure to keep the refrence point consistant.
(I don’t think I explained myself very well. Any questions?)
It pains me immensely to say it, what with him being my little brother and all, but he’s right, you know.
<shakes fist at sky>
Bah!
Phil, just me
Re: Re: Tread Mills
Forgive me for not reading all of the posts on this. Contrary to the physics professors who rely on math, and the “guessers” who simply go with their gut, I try to be somewhere in between. So far it sounds like Ken Fuchs is offering the most accurate answer based on my own common sense and limited physical data.
Running with your knees high means you’re lifting your legs up, but you just keep putting them back on the level ground. When the ground is tilted, you’re putting them down at a higher point, and transfering your weight to them in less extended positions. I think this will use more energy.
It’s similar to running up a hill, but you aren’t doing the “work” of lifting yourself against gravity. I don’t know the physics language for this, but it’s something like this. Push your car 100’, up a hill, and then turn it around. Will it take more, less or the same amount of energy to push your car back to where it started? Less, of course, you did all that work fighting gravity on the way up.
I haven’t ridden a unicycle on an inclined treadmill before. But you don’t have to take steps. You have to lean into the hill, but because you’re not going anywhere, I don’t know if there is any significant difference in the amount of energy you need to keep riding that way.
Re: Tread Mills
gluteous maximus <gluteous.maximus.dyubn@timelimit.unicyclist.com> wrote:
> You won’t make any vertical progress as long as your speed matches the
> belt’s speed, but you’re still simulating moving up an incline.
The most important aspect of hill climbing is still missing from a
stationary inclined treadmill: The increase in potential energy.
It may be harder to balance a unicycle on an inclined treadmill versus a
level treadmill since balance corrections in a forward direction are
harder than those in a backward direction. However, the increase in
potential energy must still be simulated and this can’t be done with
normal treadmill and unicycle. For example the unicyclist can’t push
against a bar to expand extra energy, since the unicycle is now attached
to a bar via the rider and the rider thus ceases be to unicycling.
Simulation of the increase in potential energy can be done by using a
brake on the unicycle. Instead of an increase in potential energy we
expend the extra energy via the brake, producing heat instead of
additional potential energy (with respect to a real hill). Without this
brake, a unicycle ride up a hill almost certainly can’t be simulated by
an inclined treadmill.
Note that simulation of a unicycle ride down a hill is probably not
possible on a treadmill without adding a motor to the unicycle to
somehow simulate a decrease in potential energy.
Sincerely,
Ken Fuchs <kfuchs@winternet.com>