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Thread: Silly Questions? Sensible Answers!

  1. #141
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by Msfab
    Its not just the moon, the sun also looks bigger.

    Not just the moon and sun! So do I !!

    What is it they say about expanding your horizons?

    Mine has expanded beyond belief wih no dancing in nearly 5 weeks!

  2. #142
    Registered User Msfab's Avatar
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by under par
    What is it they say about expanding your horizons?

    Mine has expanded beyond belief wih no dancing in nearly 5 weeks!

    So what do we have to look forward tonight?

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    Re: Silly Questions? Sensible Answers!

    With all this talk about cows and cats:-

    Why are the two things cats seem to like most: cows milk and fish, the two things they're never going to come across in the wild? Cats are spectacularly badly adapted to milk cows and are terrified of water...

  4. #144
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by philsmove
    Why does the moon seem bigger near the horizon

    Than when its higher in the sky

    And no goggling
    Sorry, I just had to, (cos I'm sad like that ) and for those of you who want to find out why, LOOK HERE and for those who can't be bothered, the simple answer is, it's all in our imagination!
    MODERATOR AT YOUR SERVICE
    "If you're going to do something tonight, that you know you'll be sorry for in the morning, plan a lie in." Lorraine

  5. #145
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    Re: Silly Questions? Sensible Answers!

    If conjoined twins participate in sports, do they count as one or two players?
    Would they have to buy two tickets if they went to the cinema or one?

  6. #146
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by FirstMove
    With all this talk about cows and cats:-

    Why are the two things cats seem to like most: cows milk and fish, the two things they're never going to come across in the wild? Cats are spectacularly badly adapted to milk cows and are terrified of water...
    But cats are really good at getting humans do take care of them so it's not a problem. Although their egos are still suffering a bit that they're no longer consdidered to be gods (Ancient Egypt) they're still happy to keep acting in that manner

    Be Well,
    Christopher

  7. #147
    Registered User David Franklin's Avatar
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by DavidY
    I don't know this one - but here's my best guess..

    Trains aren't entirely solid unyeilding blocks- the windows or metal bodywork will tend to have a little "give" in them. Suppose the wasp hits the window. The window will deflect ever so slightly relative to the rest of the train and then bounce back. The rest of the train wil continue unaffected.
    Is it mean of me to point out that wasps are significantly more yielding than trains are? But although in real life the wasp and train window will deform, this is somewhat of a red herring - in the "schoolboy" analysis with an infinitely rigid wasp and train, the train never comes to a stop either. Think conservation of momentum.

    There are lots of ways of looking at this, from schoolboy physics to considering the individual atoms of train and wasp. But the line:
    If the wasp is stationary and in contact with the train, then the train must also be stationary
    is bogus in all of them.

  8. #148
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    Re: Silly Questions? Sensible Answers!

    How do you know when you run our of invisible ink
    If you're born again, do you have two bellybuttons
    If superman is so smart, why does he were his underpants, on the outside of his trousers
    Before they invented drawing boards, what did they go back to

  9. #149
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by David Franklin
    Is it mean of me to point out that wasps are significantly more yielding than trains are? But although in real life the wasp and train window will deform, this is somewhat of a red herring - in the "schoolboy" analysis with an infinitely rigid wasp and train, the train never comes to a stop either. Think conservation of momentum.

    There are lots of ways of looking at this, from schoolboy physics to considering the individual atoms of train and wasp. But the line:
    "If the wasp is stationary and in contact with the train, then the train must also be stationary"
    is bogus in all of them.
    Sounds plausible though..........

    Yeah ok, it's relative momentum - same answer as Wayaay Bird's original question


    Christopher

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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by wayaay bird
    If conjoined twins participate in sports, do they count as one or two players?
    For gentle sports eg bowling - they'd only count as one player.
    Quote Originally Posted by wayaay bird
    Would they have to buy two tickets if they went to the cinema or one?
    Two seats = two tickets

    What else you got?

    Christopher

  11. #151
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    Re: Silly Questions? Sensible Answers!

    Why Do they say it's raining cats and dogs?

    that one has always puzzled me?
    cause it's not like that would happen?

    vickyx

  12. #152
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    Re: Silly Questions? Sensible Answers!

    if it took a man a week to walk a fortnight would would it take for him to dry himself?



  13. #153
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by Vicky
    Why Do they say it's raining cats and dogs?

    that one has always puzzled me?
    cause it's not like that would happen?

    vickyx
    It used to happen - pets used to sleep on top of thatched roofs, when it rained hard, the cats and dogs slipped off the thatch, hence raining cats and dogs...


  14. #154
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by Martin
    It used to happen - pets used to sleep on top of thatched roofs, when it rained hard, the cats and dogs slipped off the thatch, hence raining cats and dogs...


    thanks for clearing that one up for me !!

  15. #155
    Registered User El Salsero Gringo's Avatar
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by DavidY
    I don't know this one - but here's my best guess..

    Trains aren't entirely solid unyeilding blocks- the windows or metal bodywork will tend to have a little "give" in them. Suppose the wasp hits the window. The window will deflect ever so slightly relative to the rest of the train and then bounce back. The rest of the train wil continue unaffected.
    Even without deflections, or yielding ("consider the spherical wasp...") then the wasp and the train are both subject to equal and opposite impulses. The rate of change of momentum - the force applied to the wasp (and so to the train) - can be considered infinitely large but in fact of zero duration. The momentum change (force integrated over time) and the energy applied to the wasp (force integrated over distance) are both therefore finite and tractable, and no contradiction occurs.

    Homework: lookup the Kronecker delta and the Dirac delta.

  16. #156
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by El Salsero Gringo
    Even without deflections, or yielding ("consider the spherical wasp...") then the wasp and the train are both subject to equal and opposite impulses. The rate of change of momentum - the force applied to the wasp (and so to the train) - can be considered infinitely large but in fact of zero duration. The momentum change (force integrated over time) and the energy applied to the wasp (force integrated over distance) are both therefore finite and tractable, and no contradiction occurs.

    Homework: lookup the Kronecker delta and the Dirac delta.
    Go on then - do WayaayBird's train one

    Christopher

  17. #157
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    Re: Silly Questions? Sensible Answers!

    In the spirit of the sillyness that is quantum physics and cancelling infinities

    Quote Originally Posted by El Salsero Gringo
    The rate of change of momentum - the force applied to the wasp (and so to the train) - can be considered infinitely large
    If momentum is infinitely large - it can be argued that the wasp and train are both moving at infiinite speeds breaking the speed of light and upsetting Einstein. They also both have infinite mass and so have infinite gravity causing a Big Crunch and the end of the Universe! Fortunately they are

    Quote Originally Posted by El Salsero Gringo
    but in fact of zero duration.
    So no-one notices

    What's integration?

    "Sensible mathematics involves neglecting a quantity when it turns out to be small - not neglecting it just because it is infinitely great and you don't want it" ~ Paul Dirac

    Take care,
    Christopher

  18. #158
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by Ghost
    If momentum is infinitely large - it can be argued that the wasp and train are both moving at infiinite speeds breaking the speed of light and upsetting Einstein.
    But it's only the rate of change of momentum that is infinitely large. Of course, that does imply a disconcertingly large force, but that's schoolboy physics for you.

    "Sensible mathematics involves neglecting a quantity when it turns out to be small - not neglecting it just because it is infinitely great and you don't want it" ~ Paul Dirac
    It should be noted that it's actually rather important not to ignore the Dirac delta-function just because it's zero almost everywhere; you might say that's the entire point. From memory[*], the quote by Dirac above refers to "ignoring" an infinite quantity that occurs in quantum field theory. Considering the procedure would give any pure mathematician ulcers, in practice seems to work surprisingly well...

    [*] I specialised in pure maths, so I was advised to avoid the ulcers(!) and not do the course covering renormalization. So this is as related to me by others...

  19. #159
    Registered User David Franklin's Avatar
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by philsmove
    If superman is so smart, why does he were his underpants, on the outside of his trousers
    If you Google on 'Jack Bauer superman underpants' you will find that:
    Jack Bauer arm once wrestled Superman. The stipulations were the loser had to wear his underwear on the outside of his pants.

  20. #160
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    Re: Silly Questions? Sensible Answers!

    Quote Originally Posted by David Franklin
    But it's only the rate of change of momentum that is infinitely large. Of course, that does imply a disconcertingly large force, but that's schoolboy physics for you.
    It doesn't exactly help that both the Kronecker delta and the Dirac delta both rely on a number which doesn't actually exist

    Quote Originally Posted by David Franklin
    From memory[*], the quote by Dirac above refers to "ignoring" an infinite quantity that occurs in quantum field theory.
    Yup - though I personally feel it extends across the board. There's a quote from Star Trek where a Vulcan looks down his nose and says
    "You actually believed Quantum Physics?! "

    Given that science rubbishes it's own theories on a fairly regular basis and given how wild some quantum physics is, I fully expect a lot of it to be regarded as madness in about 50 years time. I could of course be wrong.

    Quote Originally Posted by David Franklin
    Considering the procedure would give any pure mathematician ulcers, in practice seems to work surprisingly well...


    Quote Originally Posted by David Franklin
    [*] I specialised in pure maths, so I was advised to avoid the ulcers(!) and not do the course covering renormalization. So this is as related to me by others...
    Very, very wise choice

    Take care,
    Christopher

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