Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math.independent

Topic: Cardinality of turning wheel
Replies: 43   Last Post: Mar 10, 2013 1:55 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
netzweltler

Posts: 293
From: Germany
Registered: 8/6/10
Re: Cardinality of turning wheel
Posted: Mar 3, 2013 4:38 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On 3 Mrz., 07:05, quasi <qu...@null.set> wrote:
> netzweltler wrote:
> >quasi wrote:
> >> netzweltler wrote:
> >> >What is the cardinality of the number of revolutions of a
> >> >turning wheel, if there is no beginning and no end to it?

>
> >> For a wheel revolving forever (both past and future), the
> >> set of revolutions is in one-to-one correspondence with the
> >> set of integers, hence has cardinality aleph-0.

>
> >Is this still true, if the wheel is revolving at infinite
> >speed, meaning, that we can see at least one revolution no
> >matter how small the time we are watching it?

>
> That's totally inconsistent with my intuition about velocity
> and time.


Do we need to define 'velocity' and 'time'? Do we need to assign an
origin, past and future to give a valid answer to the question "What
is the cardinality of the number of revolutions of a turning wheel, if
there is no beginning and no end to it?"

> I assumed that instants of time could be represented
> one-to-one as points on the real number line, and that there
> exist real numbers a,b with 0 < a <= b such that at any
> instant of time, the velocity v of the wheel, expressed in
> revolutions per unit time, is between a and b inclusive.
>
> quasi




Date Subject Author
3/2/13
Read Cardinality of turning wheel
netzweltler
3/2/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/2/13
Read Re: Cardinality of turning wheel
quasi
3/2/13
Read Re: Cardinality of turning wheel
netzweltler
3/2/13
Read Re: Cardinality of turning wheel
William Elliot
3/3/13
Read Re: Cardinality of turning wheel
quasi
3/3/13
Read Re: Cardinality of turning wheel
netzweltler
3/3/13
Read Re: Cardinality of turning wheel
quasi
3/3/13
Read Re: Cardinality of turning wheel
netzweltler
3/3/13
Read Re: Cardinality of turning wheel
quasi
3/3/13
Read Re: Cardinality of turning wheel
netzweltler
3/3/13
Read Re: Cardinality of turning wheel
Brian Chandler
3/4/13
Read Re: Cardinality of turning wheel
netzweltler
3/3/13
Read Re: Cardinality of turning wheel
quasi
3/3/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/3/13
Read Re: Cardinality of turning wheel
quasi
3/4/13
Read Re: Cardinality of turning wheel
netzweltler
3/4/13
Read Re: Cardinality of turning wheel
quasi
3/4/13
Read Re: Cardinality of turning wheel
Shmuel (Seymour J.) Metz
3/5/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/5/13
Read Re: Cardinality of turning wheel
netzweltler
3/5/13
Read Re: Cardinality of turning wheel
quasi
3/6/13
Read Re: Cardinality of turning wheel
netzweltler
3/6/13
Read Re: Cardinality of turning wheel
quasi
3/7/13
Read Re: Cardinality of turning wheel
netzweltler
3/7/13
Read Re: Cardinality of turning wheel
quasi
3/8/13
Read Re: Cardinality of turning wheel
netzweltler
3/8/13
Read Re: Cardinality of turning wheel
quasi
3/8/13
Read Re: Cardinality of turning wheel
netzweltler
3/8/13
Read Re: Cardinality of turning wheel
quasi
3/8/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/2/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/3/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/5/13
Read Re: Cardinality of turning wheel
K_h
3/7/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/7/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/3/13
Read Re: Cardinality of turning wheel
Shmuel (Seymour J.) Metz
3/7/13
Read Re: Cardinality of turning wheel
Frederick Williams
3/10/13
Read Re: Cardinality of turning wheel
Shmuel (Seymour J.) Metz

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.