ed_crouch
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| posted on 16/5/06 at 09:41 PM |
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Its hard to measure the speed of light: you'd need a VERY accurate stopwatch
Did you know that as a travelling object approaches the speed of light, it gets longer in the vector direction in which it is travelling?
No-one actually gives a stuff, its just Physicists theorising.
Ed.
I-iii-iii-iii-ts ME!
Hurrah.
www.wings-and-wheels.net
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Liam
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| posted on 16/5/06 at 09:51 PM |
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quote:
Did you know that as a travelling object approaches the speed of light, it gets longer in the vector direction in which it is
travelling?
Isn't that only as measured by another observer?
Someone stop us
Liam
[Edited on 16/5/06 by Liam]
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MikeR
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| posted on 16/5/06 at 09:53 PM |
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you see this is where i find it all b*ll*cks.
in my non physics head the speed of light is just a number. So if i'm going at a smidgen slower than the speed of light and i stick my arm out
of the side of the seven and fire a gun ...... the bullet is going to go ...
amost speed of light + speed of bullet.
it suddenly 'stopping' accelerating due to the speed of light - hows that? the bullet doesn't know to slow down cause of some
theoretical thingy.
makes no sense to me!
plus what if i move my hand? its going almost speed of light + how fast i can move my hand. can i suddenly not see it?
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JoelP
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| posted on 16/5/06 at 10:01 PM |
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google the michaelson-morley experiment, thats a good start.  It seems an odd law because its very different to everyday life, sadly, we have to
take these things into account as our cars get faster and speedos less accurate
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Liam
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| posted on 16/5/06 at 10:04 PM |
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either how stuff works or wikipedia has a good introduction to relativity i think. I say introduction, but it very quickly gets mindbending
Liam
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trogdor
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| posted on 16/5/06 at 10:56 PM |
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the simple way i think of it is that using the simple equation:
speed = distance / time
if u fire a bullet while u are travelling close to the speed of light it can't go faster than this so to keep the equation balanced the time it
takes to travel a set distance will decrease.
this effect does happen while we are moving i beleive but is so minute that it would never register. light does travel at 300,000,000 metres per
second after all!
oh to answer mikeR about the bullet not accelerating, it does the time passing while it accerlates will slow down. ie a second for the bullet will
last a longer time to an observer not moving!
physics is a very weird subject once u get to extremes. also just to hurt every ones head somemore light is a wave and a particle at the same time!
[Edited on 16/5/06 by trogdor]
[Edited on 16/5/06 by trogdor]
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NS Dev
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| posted on 16/5/06 at 11:15 PM |
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aye, wave packets, synch that one,
back to bullets?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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trogdor
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| posted on 16/5/06 at 11:18 PM |
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its strange how little we know about the world around us, in physics there is one set of equations and ideas for very big things such as galaxies etc
and a completley different set up when u get really small down to molecules and atoms etc. they don't know enough to combine the two.
its the same in oceanography, we know such and such happens, but we don't know why.
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NS Dev
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| posted on 16/5/06 at 11:21 PM |
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Yep, it's what makes our world so great and why we should make the most of every minute on it!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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trogdor
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| posted on 16/5/06 at 11:26 PM |
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to true, was one of the reasons i decided to do oceanography, we know so little about the oceans its untrue.
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DIY Si
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| posted on 16/5/06 at 11:29 PM |
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The equations are the same, just the variable affects are different. As you approach the speed of light time itself slows down, so that the bullet
will travel faster than you are but only because time has slowed. To a stationary observer the bullet sppeds away just as you would expect, but since
it's technically impossable to reach the speed of light, does it really matter? You'd need all the energy in the universe and more to
achieve that speed, due to having an infinite mass at v=c. Also, as you achieve the speed of light/cross an event horizon ( there's a phrase to
confuse the masses! ) you become infinitely long in an infinitely long space of time. Discuss.
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trogdor
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| posted on 16/5/06 at 11:37 PM |
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its wierd that if u had enough space u could travel to the future! admitty u would be so far away from where the time u would want to get to would
be....... unless u went halfway then came back!
blackholes are strange too, physics as we know it completley breakes down and is meaningless.
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DIY Si
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| posted on 16/5/06 at 11:43 PM |
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It's not possable to travel forwards in time, however, if you achieved the speed of light time technically stops/slows infiintely. So by the
time you come back/slow down again, you have aged less than everyone else, hence you are in someone elses past, but your present. Wierd hey?
Agreed about the black holes though. They have event horizons, which screw all manner of things up! Such as space, time, distance, mass.......
Basically destroys all known physical laws! Good fun eh?
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trogdor
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| posted on 17/5/06 at 12:25 AM |
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if i was being pedantic i would say were are all travelling forward in time! but anyways that is true u would not atcually travel through time! it
just sounds cool! there was that experiment with a jumbo jet and two atomic clocks that were scronized and then one of them was flown around the
world. because the jet had been travelling, time would be running slower compared to the one that was stationary.
when the clock got back it was found to be few milliseconds out showing this time dilation effect.
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C10CoryM
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| posted on 17/5/06 at 02:18 AM |
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Robert, unless you are building an F1 car don't worry about brake line length. You will never notice the difference. Make sure both sides have
the same length flex-hose though.
This whole speed of light thing sounds a lot like sailing off the edge of the earth to me. In 300years people are going to laugh at us because we
think that something magical happens at a specific speed . There is still light in front of you while you are travelling above light speed so its
not going to get dark or anything. Just like if the pilot farts when he is super sonic the gunner still hears it.
So what about the lady near me that has slowed down light? Does that mean this magic stuff happens sooner?
Cheers.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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caber
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| posted on 17/5/06 at 03:51 AM |
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Back to the serius stuff for Mike, The reason cats die in falls from between 3rd and 6th floor but not above is that they stop panicing and get into
flight mode with all paws spread out this increases aewrodynamic drag and reduces terminal velocity sufficiently for a rough but safeish landing. It
doesn't always apply to overweight or skinny cats. Amazing animals really!
Caber
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tks
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| posted on 17/5/06 at 06:57 AM |
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yeah!!
or another one :
a bullet wich is fired 90degrees with the ground.. will reach the ground in the same amount of time if it just where hold on the same high and if let
to fall.
Offcourse like many pysics rulez this one is only in the vacuum environment (space)
The above comments are always meant to be from the above persons perspective.
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Macbeast
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| posted on 17/5/06 at 07:10 AM |
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Fired parallel to the ground, surely ??
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Bob C
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| posted on 17/5/06 at 09:04 AM |
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Who said you can't travel forwards in time???
I'm doing it right now (without any special equipment)
I like to use the rate of 1 second per second, I find it less confusing that way.
cheers
Bob
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tks
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| posted on 17/5/06 at 09:19 AM |
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yeah!!
parallel to the ground is one rule, no air is the second...
The bullit will be moving but also falling because of the graveti..
the only thing wich depends on the bullet speed is the distance wich it travels..
sow in fact it still coud kill someone you just need speed sow you don´t need time, when you don´t need time.. the heigh loss isn´t a point because
you already reached your goal.
think about it.
if it where shot/let fall from 5meteres from the ground and it took him 1sec to reach the ground.
if the bullet travels 2500meters/second
you could shoot someone at 100meters
with only a heigh loss of :
2500/100 =>25
1 / 25 = > 0.04seconds
5/0.04=> 0.008meters 8 milimeters! accurency with that bullit speed...
now you know wy the sniper rifle has that tremendous bullit speed
thanxs of this rule tennis is also sow great!!
Tks
The above comments are always meant to be from the above persons perspective.
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02GF74
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| posted on 17/5/06 at 09:46 AM |
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quote:
Originally posted by MikeR
pah ..... now, can someone explain to me why a cat can survive a fall from seven story building but not 6?
I will add to what someone has added.
There was a study done in USA (obvioulsy they weren;t catapulting cats out of windows but aanlysing vet data).
Cats have lose skin - useful for getting away from predators.
When they fall down from up to 3 storeys, they do the 'land on 4 feet thing' and survive.
Above 6 storeys, they have time to stick their paws out, the loose skin between the limbs acting as a parachute, a bit like the flying squirrel thing,
and glide down.
In between 3 and 6 storeys, it is splat.
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02GF74
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| posted on 17/5/06 at 09:50 AM |
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quote:
Originally posted by tks
parallel to the ground is one rule, no air is the second...
The bullit will be moving but also falling because of the graveti..
I am not sure about this. Isn't there something about escape speed?
Assuming there is no air resitance, three things will happen depending on the bullet's speed.
a) it slowly falls back to earth
b) it continues to oribit around the earth forever (think of satellites)
c) it goes in a straight line, leaves the earth and travels on forever....
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02GF74
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| posted on 17/5/06 at 09:53 AM |
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quote:
Originally posted by tks
or another one :
a bullet wich is fired 90degrees with the ground.. will reach the ground in the same amount of time if it just where hold on the same high and if let
to fall.
Offcourse like many pysics rulez this one is only in the vacuum environment (space)
Are you saying the time from firing to coming back down to earth is the same as if it were dropped from the height it gained???
No, it can;t be can it.
The bullet going upwards eventually slows down and stops (gravity and air resistance). The time taken for it to fall back to erath will be the same
as if it were droppped from that point; the will be time taken for it to reasch that point hence the two times will not be the same.
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ufe777
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| posted on 17/5/06 at 10:06 AM |
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Will it matter?
Scientist's answer: Yes
Engineer's answer: No
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britishtrident
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| posted on 17/5/06 at 12:52 PM |
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A Reading from the Book of Armaments, Chapter 4, Verses 16 to 20:
Then did he raise on high the Holy Hand Grenade of Antioch, saying, "Bless this, O Lord, that with it thou mayst blow thine enemies to tiny
bits, in thy mercy." And the people did rejoice and did feast upon the lambs and toads and tree-sloths and fruit-bats and orangutans and
breakfast cereals ... Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the
counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth
to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the
direction of thine foe, who, being naughty in my sight, shall snuff it."
-- Monty Python, "Monty Python and the Holy Grail"
[Edited on 17/5/06 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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