Elastomania is played on a space anomaly!

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onlainari
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Elastomania is played on a space anomaly!

Post by onlainari »

http://www.ratol.fi/~vnaatane/elma/

Air friction is not taken in consideration which makes those calculations a bit false UNLESS.. there is no air friction. ..but well... I guess if the friend who is assisting me is willing to create all those ballistic graphs etc maybe then....The shape of the anomaly is also unknown. Instead of a round object it could be some alien level object wandering in space.

Also Those calculations aren't based on pure facts. You have to estimate the size of rim,weight of kuski and the weight of the bike. Also there could be tiny miscalculations by pixel here or there. So don't take it too seriously,it's just "giving a direction". I estimated the wheel to be 16" , bike weight 57kg and kuski 48kg.

The elma bike doesn't have any friction in the wheels bearings and the bike and polygons are non-elastic objects. Sliding friction is 1,because when you press brake ,it doesn't slide at all. Then the static friction is in a way also 1 ,because the bike doesn't start to slide on uphill when brake pressed down. You may see sometimes some friction kind of movement when you have put pressure on one wheen on big speed and it kinda slides with the "shake-effect"

related topic:
http://www.moposite.com/mopolauta/viewt ... ht=physics
Last edited by onlainari on 9 Nov 2004, 00:07, edited 6 times in total.
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Post by John »

that is very coal stuff onla, nice :)
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Post by The_BoneLESS »

Some sick physics... 8O
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Post by Ky.Jelly »

that is awesome, damn he is good
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Post by Revolt »

ye very nice
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Post by Domovoy »

Imo gravity is close to 2,394 "wheels"/second**2. But you got 2,549 "wheels"/second**2. :?
Last edited by Domovoy on 9 Nov 2004, 16:42, edited 1 time in total.
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Post by Zweq »

ye maybe u could choose ur playing planet/moon in elma 2, different levs on each planet/moon of course. would take much more time to learn different gravities, maybe people would specialize on the planet/moon they like the most. ;)
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Post by AtmaWeapon »

I don't get it :S
Hello world.
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Post by Zweq »

ive heard that one before
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Post by Phillip »

Are you sure the gravitational acceleration is not constant?
On your pictures you say it is 1.00m/s^2, then higher up it is 0.95m/s^2, and even higher it is 0.907m/s^2. Now, when you calculated those values you assumed acceleration was constant, or? (If acceleration is not constant, then calculating the actual acceleration based on the time it takes to fall from different heights gets really complicated)

I would think gravity is actually constant in elma, but hey, nice calculation anyway :)
(If gravity is constant, then no calculations can be done about the radius of the elma planet :cry:)
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Post by milagros »

gravity os constant, only probablem is that frames at replays are not saved exactly every 0.0333333333333sec
might differ quite much so that's why so replays are 'waving' around each other when merging
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Post by onlainari »

I didn't think gravity was not constant, it may seem liek it is not constant but those changes are so huge because of the so small M. On earth the gravitational pull is some 9.81 somewhere at 1km and then 9.83 at surface or something...ye as mila says it a constant


a' I got I just turned s=.5at^2 to a= s/.5t^2 and then calculated a and noticed that it gives different values between so little height differences.

At that moment I thought this F = G*M*m / r^2. If so small changes on r (from 0.49meter to 4.03meter) had so big influence on that experimental a I got from the calcs I just kept doing ..
(If gravity is constant, then no calculations can be done about the radius of the elma planet )
F = ma ja F = GMm/r^2 --> ma = GMm/r^2 <-> a = GM/r^2

a1 = GM/(r+r1)^2 a1 and r1 are known
a2 = GM/(r+r2)^2 a2 and r2 are known ...


if I had taken 1sec drop from different distances from the core , that would have been better. now the acceleration medium plays role the longer the drop etc
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Post by Juble »

Zweq wrote:ye maybe u could choose ur playing planet/moon in elma 2, different levs on each planet/moon of course. would take much more time to learn different gravities, maybe people would specialize on the planet/moon they like the most. ;)

ye that sounds awsome :wink:
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Post by ribot »

or maybe elma is played in a special room like one of those non gravity spaces that airplanes create. or wait, maybe it's in a virtual world not really too similar to any physical one?
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Post by Phillip »

onlainari wrote:a' I got I just turned s=.5at^2 to a= s/.5t^2 and then calculated a and noticed that it gives different values between so little height differences.
Those formulas are only correct if a is constant (you can't use them when a varies). If a is constant (which it is) you should get the same value for a when measuring different heights
(If gravity is constant, then no calculations can be done about the radius of the elma planet )

a1 = GM/(r+r1)^2 a1 and r1 are known
a2 = GM/(r+r2)^2 a2 and r2 are known ...
If a1 = a2 (which it is) then r is infinite, so I was a bit sloppy there (it is determinable). According to this the elma planet is infinitely large (the surface is completely flat and gravity is independent of height). This is of course not realistic (in the real world), and one alternative way to view it is this:

You could assume that the gravity in the "real" elma world (:lol:) is just approximated to that constant value a in the game, then assume that the elma planet has the same mass density as the earth or the moon or whatever. Then you could calculate the radius from:

a = GM/r^2
where M = density*(4/3*Pi*r^3)
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Re: Elastomania is played on a space anomaly!

Post by Phillip »

onlainari wrote:Sliding friction is 1,because when you press brake ,it doesn't slide at all. Then the static friction is in a way also 1 ,because the bike doesn't start to slide on uphill when brake pressed down.
Actually the friction coefficient (the ratio between the normal force and the braking force) has to be larger than 1 for this to be true, it is probably also infinite :?


Anyway, I really liked your calculations, don't want to ruin them in any way :oops:
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Post by onlainari »

how about making tests where you drop the bike like 10cm from the surface and take the a ..and then you drop it from as high as possible for 10cm also? can you calc some bajs then...

I don't really now bother my head with this atm ..maybe I read more carefully some itme when got teh tim0r and glad to hear you like it :X

Feel free to download the pages and make a page without any flaws , would it end up to be more like an empty page without no knowledge of anything ? cuz I wane teh all information about this little game and all imaginary possibilites there is :X so I had to make one myself with my restricted physics skills :P

How about the measuring of the topspeed? Do you think it is some what "direction giving" at least?

Personally I think the topspeed measuring needs more testing on different lengths etc, if the .rec flickers like 0.03 as mila says
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Post by Phillip »

Nah, your measurements are ok, and the calculation of top speed seems right :)

The only thing I would do different is this:

a is constant: The different measurements gave three different values, but the differences are just because of inaccuracies. Let's take a to be the mean value of them (0.95m/s^2).

Now let's assume the elma planet consists of the same materials as earth (same density). For the earth we have:

a = 9.81m/s^2 = GM/r^2 = G*(density)*(4/3*Pi*r^3)/r^2 = 4/3*Pi*G*density*r

As we see, if all planets had the same density, then the gravitation on their surface is proportional to the radius. Since the elma world has a gravity of about one 10th of the earth's, the radius has to be about one 10th of the earth's. More accurately, the earth's radius is about 6350 km (as far as I remember), which means the radius of the elma world is about 6350*0.95/9.81 km = 615km

The distance around the elma world would be 2Pi times this, roughly 3863 km. At top speed a ride around the planet would take 51 hours and 30 minutes, a rather small planet :)
Last edited by Phillip on 10 Nov 2004, 17:09, edited 1 time in total.
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Post by Jeppe »

Freak 8O
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Post by Behk »

lol Phillip ;DD
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Post by Phillip »

Jeppe wrote:Freak 8O
So, höyling a stupid motor bike game for hours and hours, year after year is ok. But if you do some interesting physics calculations (which just takes a few minutes) you are a freak? Does anyone see the irony here? :lol:
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Post by milagros »

no
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Post by teajay »

So our fellow kuski is just a minor?? Who would've though that. :P
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Post by kinghias »

i quite agree with phillip

btw. really nice calculation although i also would've calculated it with a as a constant...
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Post by onlainari »

I have had some mix up with the properties of "constant" gravity, so some of my earlier posts may not make sense. :)

The page is updated now with new information. http://www.ratol.fi/~vnaatane/elma/
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Post by Tisk »

I made some calculations some time ago and now read some of these calculations.

I got that gravity force in "elma planet" is about 1.6 m/s^2, i assumed the Kuski is about 180cm tall and got the wheels size from that...

A thing to note when While dropping in a max size external level is that mopo reaches it's maximum speed before reaching ground.

About friction, friction in elma is not 1, it's a lot bigger. May It be noted that friction can vary only between 0 and 1.

With little try i managed to hang on 80 degrees steep ground. Knowing how steep the ground is, the friction factor can be calculated straight from tan x. tan 80 would be more than 5. As it's impossible, some other force is holding tire in ground like magnet or glue... :P

I understood that the page whose link there was that assumed that elma planets surface is same as length of max size of level. It just wouldn't work as a level can have lots of ground in it or very little, in so little planet it would noticebly affect the gravity in different places, but no such difference is noticable in elma.
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Post by zworqy »

Friction can't be more than 1, when talking about friction :arrow: 1 = infinity.

Friction 0 means that an object can keep rolling forever, it never slows down.

Friction 1 can only be achieved by glueing the object to the ground, so it doesn't budge.
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Post by Abula »

zworqy wrote:Friction can't be more than 1, when talking about friction :arrow: 1 = infinity.
That's true, in reality, but as we know Elma is a bit different...
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Post by Juski »

You can hang in the ceiling of the slowness levels, so that is pretty good friction. And for that too happen teh friction must be very high, but what holds it up is the suspension squessing too teh ceiling cause you can only hang on small corners, i dont really what this proves, but the friction still can't be over 1 right?
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Post by Phillip »

zworqy wrote:Friction can't be more than 1, when talking about friction :arrow: 1 = infinity.
Nope, there is no magic friction limit at 1 (I'm talking about the ratio between the friction and the normal force)

If you ride in a car, and step on the brakes, there is no reason why the car should be able to brake at less than 9.81 m/s, and not more. Friction happens at the micrcoscopic scale. All friction is because of some cog-like effects, and as I said, there is no magic limit at 1 (allthough a lot of people, including teachers, seem to think this)
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Post by Juski »

Well, philip if the friction was 1, then when you do hit the brakes, the car would stop instantly, i dont know how you count the friction, but 1=infinity the way we measruses it, and glue and magnets dont raise the friction, they just(atleast magnets) change the force of or changes direction of the gravity in a small scale....
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Post by ribot »

apparently there is different friction units? as 1 is not the force but some relative number, the friction grows for example when a bigger object is being accelerated.
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Post by Phillip »

Juski wrote:Well, philip if the friction was 1, then when you do hit the brakes, the car would stop instantly
If you read my post I actually wrote the usual definition of friction, ant that's not what would happen (with my definition of friction that is... ;) )

Just an example to explain my definition:
Let's say a box on the ground weighs 100 N. Then the normal force is 100 N (the force acting on the box from the ground), since the box doesn't fall through the ground.

Now, in this case the box moves at a constant speed if you push horisontally with 80 N. The friction is then defined as the ratio between the two forces: 80/100 = 0.8.

This ratio is normally called the "coefficient of friction" (often denoted by the greek letter "mu")

This ratio is what I was talking about, many people seem to think it can't exceed 1 (which is wrong). Sorry if this was not what you were talking about... :roll:

And if this ratio is 1 the car won't stop instantly, it will stop with an acceleration equal to the gravitation (9.8 m/s^2)

What kind of definition are you using? Don't think I've ever heard of it.
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Post by zworqy »

Phillip wrote:What kind of definition are you using? Don't think I've ever heard of it.
I look at it like this: You have an object on a board of some material. Raise the board in one end and measure the angle at which the object starts sliding off. If the angle is 45 degrees, the friction is 0,5 etc. If the board reaches 89,999999... degrees before the ojbect slides off, the friction is 0,9999999...

So it's easy to see that the friction can't exceed 1.
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Post by Phillip »

zworqy wrote:If the angle is 45 degrees, the friction is 0,5 etc. If the board reaches 89,999999... degrees before the ojbect slides off, the friction is 0,9999999...
That's a quite different definition than the usual one. It seems that you define it as sin(angle).

However, saying that "friction can never exceed 1" with this definition is meaningless, it is trivial. It has no physical meaning, because it is the same as saying that "friction force can never be larger than infinity".
(nothing can be greater than infinity)

The definition normaly used in physics literature is equivalent to tan(angle), and for your example,"mu" would be tan(89.9999...) = (a very large number). Are you sure you are not mixing things up a bit?
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Post by milagros »

anyway sin(45 degrees) is not 1/2 (but sqrt(1/2))
phillip is right in this friction discussion, ok?
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Post by SveinR »

milagros wrote:anyway sin(45 degrees) is not 1/2 (but sqrt(1/2))
Hmm isn't it (sqrt 2)/2 ?

Doesn't matter but :)
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Post by milagros »

sqrt(1/2)=1/sqrt(2)=sqrt(2)/2 btw.
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Post by SveinR »

milagros wrote:sqrt(1/2)=1/sqrt(2)=sqrt(2)/2 btw.
Fine i apologise for my inferior math skills :)
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Post by Phillip »

milagros wrote:anyway sin(45 degrees) is not 1/2 (but sqrt(1/2))
Of course, my mistake. But this only makes that strange definition even more unreasonable.
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Re: Elastomania is played on a space anomaly!

Post by abruzzi »

a bump. anyone to say anything new?
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Post by Mawane »

zworqy wrote:I look at it like this: You have an object on a board of some material. Raise the board in one end and measure the angle at which the object starts sliding off. If the angle is 45 degrees, the friction is 0,5 etc. If the board reaches 89,999999... degrees before the ojbect slides off, the friction is 0,9999999...

So it's easy to see that the friction can't exceed 1.
actually, xiph and igge proved that its possible to hang on more than 89,99999 with igge's screenshot xD
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Re: Elastomania is played on a space anomaly!

Post by Igge »

Heah, had forgotten about teh.

http://up.k10x.net/slfvphlbopsvf/sickhang.png : D
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Re: Elastomania is played on a space anomaly!

Post by Mawane »

wtf, wasnt like >90° ? dame
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Re: Elastomania is played on a space anomaly!

Post by Igge »

That would be impsy. I guess the limit is either 89.9* or 90* exactly.
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Re: Elastomania is played on a space anomaly!

Post by pawq »

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yea, very much >90 -.- its 86 degrees exactly
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Re: Elastomania is played on a space anomaly!

Post by abruzzi »

that's nothing. i once hung on a 160 degrees surface
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Re: Elastomania is played on a space anomaly!

Post by abruzzi »

sorry for double post, but the editing doesn't seem to work for me atm.

soo i hanged like that, i'm not sure at the moment if it was islands but for sure i did this. of course there was a slight wheel pressure, but hey, i hung

http://up.k10x.net/ggaspjjvuanqa/snap07.JPG


maybe someone ambitious can prove this somehow, i'm busy right now
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Re: Elastomania is played on a space anomaly!

Post by Madness »

Yeah it's possible, I managed the same. :)
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Re: Elastomania is played on a space anomaly!

Post by Igge »

Oh yeah, done that too. Also, there is the WTH hang from the start platform. That must be like 89*
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