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Al P
Lv 7
Al P 發問於 Science & MathematicsPhysics · 1 十年前

A twenty four hour clock has metric?

A 24 hour clock has metric ds^2=r^2dΦ^2+dr^2 where r=4Φ and

marks time every half-hour What is the total distance traveled

during odd intervals?

更新:

Thank you for answering.

What a beautiful mathematical clock I

have designed. I might just build this.

I'll leave more detail if nobody gets this.

更新 3:

The question is not ambiguous. Consider

the nature of clocks and apply inductive

reasoning.

Again, I must pat myself on the back for

creating such a B_E_A_U tiful clock.

更新 4:

http://i985.photobucket.com/albums/ae336/sdopqwe82...

Here is the 12 hour clock I made

similar to the one referenced below.

I know the answers to both questions

I believe. Said questions, without

a touch of inductive reasoning, are

not interesting to me. So, if one enjoys

the hunt please do so by all means. If not,

don't waste your time. This is the first

time I have asked such a question.

http://answers.yahoo.com/question/index;_ylt=Al6ak...

qid=20100928114655AAQkOVR

更新 6:

Inductive reasoning:

1. a clock has zero displacement after 24 hours. (one day)

2. this clock marks time and thus distance in half-hour intervals(plural).

3. hence, there are 48 intervals.

4. guess what number an odd interval starts with.

5. guess what number an odd interval ends with.

This is a reasonable "first" educated guess for this simple puzzle.

The truth be told, had anyone provided a number based on the

"plural" for one day, BA would have followed.

1 個解答

相關度
  • smci
    Lv 7
    1 十年前
    最愛解答

    A spiral: ds^2 = (r dΦ)^2 + dr^2 where r=4Φ

    Write everything in terms of Φ ; then r=4Φ, dr=4dΦ

    ds^2 = (4Φ)^2 dΦ^2 + (4dΦ)^2 = (4dΦ)^2 (Φ^2 + 1)

    ds = 2dΦ √(1 + Φ^2)

    Integrating by parts, s = Φ√(Φ^2 + 1) + arcsinh(Φ) (+C)

    But there's no point in that until you clarify the following:

    >marks time every half-hour

    => Very ambiguous. Does that mean "one continuous revolution (Φ sweeps 2π) in half an hour"?

    or that it is discrete and only advances on half-hour increments? and does Φ move 2π or (2π/(24*2)) in a half-hour? You need to clarify.

    >What is the total distance traveled during odd intervals?

    "odd intervals" of what? the hour digit? the half-hour increment? full revolutions of 2π?

    EDIT: Al, it's not that nobody "got this", it's that you were utterly ambiguous! All you needed to do was answer the questions, dude.

    So from the Wikipedia link, apparently you meant "a continuous 24 hour clock (=> Φ sweeps 2π in 24hrs, π/24 in a half-hour)".

    But you STILL haven't answered what you meant by "odd increments":

    1am to 3am? (odd increments in hours)

    1am to 2am? (odd increments in half-hours)

    something else? (odd increments of whole days?)

    Try answering that this time, grrr.

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