Imagine a plane is sitting on a treadmill

Be grateful you still had fingernails.

The only way for the wheel to make progress along the belt is to go faster than the belt which it can't do at anything above 0mph according to interpretation 2.

What if the wheel goes the same speed as the belt (eg 100mph)? Bah, troll, go away.

Blunt spoons???

Piggin' luxury!

Its your interpretation.

After thinking entirely too much about about angular velocity and rolling resistances, I thought of this... (it does not warrant its own thread)

Get a gym treadmill and a ball the size and similar weight to a bowling ball, no imagination needed on this front sin
Put the bowling ball on the treadmill. The ball is not moving, the treadmill is not moving.

Before I ask the question, I would like to stipulate a few assumptions, one of which sits outside of reality just for simplicitys sake.
1. We assume ZERO rolling resistance. (the unrealistic assumption)
2. We assume zero wind resistance
3. The conveyor is level.
4. The treadmill is set to run at a certain speed and does whatever it needs to do to get to that speed.
5. NOTHING is imaginary or impossible or unconventional other than clause 1 (I hope that is enough to shut up the pedants and trolls!).

Now start up the treadmill.

Does the ball spin in place or does it move with the treadmill?

Edit, I did not think this through enough, the intuitive and the not-so intuitive reasons both have the same outcome so its a redundant question. That will teach me to click "post" before thinking it through Sorry, ignore me.

Wouldn't it roll off?

Its like pulling a tablecloth off a table decked with dishes. Start off too slow and crash, but start off fast and it stays put.

It's just as simple as every single other question/scenario on here. You just take the ball, think what forces are acting on it, then use Newton's 2nd law (in the horizontal, vertical and angular directions) to work out how it accelerates.

Edit: @eurovol, *if* you assume no rolling resistance, it would be impossible to pull the belt slow enough to prevent the ball spinning

No rolling resistance=No force on ball=No moment=no movement

Oooh, I got one!

Rolling resistance and friction are two different things. Just because rolling resistance is zero doesn't mean there is no friction. You just need a ball and conveyor that deform perfectly elastically with no energy loss, they will roll forever then (ie no rolling resistance) but there could still be friction if you try to slide the ball across the conveyor.

I have decided that over my Christmas holidays to read all the comments on this thread

Could you do it with a rolling stone?
Or maybe I should ask, would you do it with a rolling stone.

Is there really only one outcome? I thought that there were 3:
All relative to external pt of ref
1.) The ball remains stationary and rolls (high coefficient of friction btw ball and belt, high belt acceleration and low moment of inertia)
2.) the ball remains stationary and slides (high mom. of inertia, very low coef. of fric. and high acc.)
3.) the ball is pulled along by the belt (low I, low acc)

they can all be reduced to being dependent on the coef of frict, mass of the ball, density, and acc. of the treadmill belt. Or am I missing something?

What can you swim faster in?
1) a pool of water
2) a pool of viscous goo

A rolling sausage gathers no gravy.

What about mustard?

If you mustard you mustard.

Marmite be worth a try though.

You're missing a diagram (I likes diagrams):

Then you bribe Mr Newton with an apple so you can borrow his 2nd law for a bit.

Condoms are more effective apparently

Condoms ?

Friction and the mass of the ball would still play a role though.

As I added to the post, I had a bit of brain freeze and got my idea all wrong. I did not feel like completely rewording it as some people had responded earlier.. I also missed out something (an assumption I forgot to state) - the coef of friction between the ball and belt would be high enough to prevent any slippage in the scenario I was thinking of. And given that premise, your answer was...

1.) The ball remains stationary and rolls (high coefficient of friction btw ball and belt, high belt acceleration and low moment of inertia)

Which is wrong The ball would accelerate in the direction of belt travel while the belt is accelerating to its specified speed and then continue along at a constant velocity wrt the belt while spinning.

Imagine this thread ending.

Maybe, in a parralell universe

Imagine Tom17 being able to spell parallel

But if the space-time continuum were the conveyor belt, and the mass was equal to zero plus the photons at a specific wavelength oscillation sinosoidially at a given frequency but with half the amplitude so that the resonant frequency of said conveyor belt was ten to the sixth lower, and a hard boiled egg of 20 grams cooked in water at exactly 100˚C for 240 seconds entered the force being the conveyor belt central and parallel with said force being the conveyor belt, and said atmosphere were a vacuum at ˚K with enough thrust of a 25kg chimpanzee's fart (female, in the middle of the ovulation cycle), after consuming 3 litres of dunkles weissbier steadily within the previous 120 minutes, would the frequency shift be enough to turn red to blue?

I was just wondering, as you do.

Professor Sin, you have ignored the implications of the Treaty of Barnstow from 1824 and the therein implicit regulations for bean disintegration in flight. I put it to you sir, that only the application of a 12 cubit layer of marmite will allow the aircraft to take off.

It never mentioned The Treaty of Barnstow when I copied and pasted it.

Sorry, I was writing that from a parallel universe where parallel is spelt parralell.

Honest

(I could have just edited it )

Hang on!

What aircraft?

I'll take half a pint of what you're drinking, sir.

I found this to be helpful, got it off "The Straight Dope" (yeah, I googled this little bitch of a riddle, it was f-in me up, what can I say?)

"A thought experiment commonly cited in discussions of this question is to imagine you're standing on a health-club treadmill in rollerblades while holding a rope attached to the wall in front of you. The treadmill starts; simultaneously you begin to haul in the rope. Although you'll have to overcome some initial friction tugging you backward, in short order you'll be able to pull yourself forward easily."

Hope this helps...

Thats a bit off-topic now isn't it?

Topic split: Post a picture of your favourite 17th Century Mathematician

Well... he was born in the 17th century, and he ain't a mathematician, but a physicist, and he's done me alright for a few patents over the years.



Sir David Brewster 1781-1868

Fruitcake extraordinaire. Responsibubble for Brewster's Law, being a cunt to small boys and died broken hearted when one of his patents for a carpet design tool turned out to be flawed and sold in the millions as the kaleidoscope to become a small boy's toy, bringing a nice touch of poetic justice to the tale.

Cheers, ya mad Scottish twit.

Brewster came from a long line of fruitcakes. He is a decendant of William Elder Brewster, who was a mad anal-retentive preacher aboard the Mayflower in 1620. If you need any proof of how much a fruitcake William Elder was, he christened his two sons, Love and Wrestling. Barkin', the lot of them.

Just delete this and the one above please.

Edit: the 2 above

What the fuck - Do you not think these posts are germaine to the tight focus of this thread???

What's she got to do with it?

They are life support for a dying thread. I respect the the threads right to die peacefully.

Oh, sin, she a ho. You havent heard?

We are the Thread Medics. Our job is to maintain life.


Is she any good?

I don't know. I haven't had time to investigate since I've been riding a tread mill with inline skates on while pushing a bowling ball and pulling on a piece of rope since tuesday. No lift off to report either.

A dying thread? HA!


It depends, you did not say if it was imaginary or not.

It is real. I have the whole experiment running on the 3rd shelf of the wardrobe. I am hoping to collect the results of the experiment fairly soon, because I am running out of eggs and dunkles weissbier, and the stench from the monkey means I have to keep the window open... and it is rather cold this time of year. Last night, a passing Skwalliuk destroyer managed to penetrate the experiment in a totally separate experiment of their own. But, when I told them that don riina didn't live here, they left.

I still wanted to argue about the bowling ball... but it's Friday and in a few hours I'm on holiday and typing physics equations on a forum is too much like work. Instead here is a pic of Hooke... He was almost a dwarf and disliked Newton. He also did some stuff with Law etc.

Gauss was a pretty clever dude too...

I'd like to hear your reasoning when you get back.

Yeh me too :-) (you can refer to the diagram in post #1070 if you like)

I am having trouble decding between these two brainiacs.

ffs there is only one mathematician worthy of a mention in this Fred



nuff said