Originally Posted by under par
So what do we have to look forward tonight?
Originally Posted by Msfab
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!
Originally Posted by under par
So what do we have to look forward tonight?
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...
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!Originally Posted by philsmove
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
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?
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 mannerOriginally Posted by FirstMove
Be Well,
Christopher
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.Originally Posted by DavidY
There are lots of ways of looking at this, from schoolboy physics to considering the individual atoms of train and wasp. But the line:
is bogus in all of them.If the wasp is stationary and in contact with the train, then the train must also be stationary
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
Sounds plausible though..........Originally Posted by David Franklin
Yeah ok, it's relative momentum - same answer as Wayaay Bird's original question
Christopher
For gentle sports eg bowling - they'd only count as one player.Originally Posted by wayaay bird
Two seats = two ticketsOriginally Posted by wayaay bird
What else you got?
Christopher
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
if it took a man a week to walk a fortnight would would it take for him to dry himself?
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...Originally Posted by Vicky
Originally Posted by Martin
thanks for clearing that one up for me !!
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.Originally Posted by DavidY
Homework: lookup the Kronecker delta and the Dirac delta.
Go on then - do WayaayBird's train oneOriginally Posted by El Salsero Gringo
Christopher
In the spirit of the sillyness that is quantum physics and cancelling infinities
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 areOriginally Posted by El Salsero Gringo
So no-one noticesOriginally Posted by El Salsero Gringo
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
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.Originally Posted by Ghost
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..."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
[*] 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...
If you Google on 'Jack Bauer superman underpants' you will find that:Originally Posted by philsmove
Jack Bauer arm once wrestled Superman. The stipulations were the loser had to wear his underwear on the outside of his pants.
It doesn't exactly help that both the Kronecker delta and the Dirac delta both rely on a number which doesn't actually existOriginally Posted by David Franklin
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 saysOriginally Posted by David Franklin
"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.
Originally Posted by David Franklin
Very, very wise choiceOriginally Posted by David Franklin
Take care,
Christopher
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