Saturday, February 19, 2005
Queen of Spades
Trip Stats
Can someone settle a physics/maths-related debate I've been having with myself the last week, since I thought of putting the speed & velocity in the above table? Which one of them should be zero? I think I'm right, because my net displacement (the "top line" in velocity) is zero, but my net distance is non-zero. But I'm not sure.
Well, I made it home last night at about 11 pm. No food in the house whatsoever, so I had to drive into Ormskirk (5 miles or so) to the 24-hr Safeway there. Mmmmm - salad bar. Then I slept till 1 pm this afternoon! I'm currently waiting for my first load of washing to finish, so I can put the second one in - my parents have much better washing facilities than I do - you don't have to iron most things after they've been in the drier!
And one final holiday highlight - while queuing in the Heathrow passport line last night, I was stood behind Olivier Rochus, the tennis player! I've sometimes wondered what I'd say to a celebrity (define that word how you will - I know who he is!) if I met one, and now I know - absolutely nothing! My main problem was actually deciding whether he was him, or his brother Christophe, who's pretty much identical-looking. If I could have told which one he was sooner (overheard one of the people he was travelling with) I'd have asked him to sign my Aussie Open hat which I had in my coat pocket. Missed opportunities.
Trip duration : 48 days 8 hours
Total distance flown : 25909 miles
Average speed : 22.3 mph
Average velocity : 0 mph
Total time in air : 54 hrs 20 mins
Total time on water : 8 hrs
Total time in Rod Laver Arena : 23 hrs 25 mins
Total time in US Customs : much longer than I wanted to
Furthest northerly point : Manchester, UK, 18/02/2005 (53.35 deg N)
(although technically York is further north,
and the flight from Boston actually went further
north still)
Furthest southerly point : Apollo Bay, Victoria, Australia, 31/01/2005 (38.75 deg S)
Can someone settle a physics/maths-related debate I've been having with myself the last week, since I thought of putting the speed & velocity in the above table? Which one of them should be zero? I think I'm right, because my net displacement (the "top line" in velocity) is zero, but my net distance is non-zero. But I'm not sure.
Well, I made it home last night at about 11 pm. No food in the house whatsoever, so I had to drive into Ormskirk (5 miles or so) to the 24-hr Safeway there. Mmmmm - salad bar. Then I slept till 1 pm this afternoon! I'm currently waiting for my first load of washing to finish, so I can put the second one in - my parents have much better washing facilities than I do - you don't have to iron most things after they've been in the drier!
And one final holiday highlight - while queuing in the Heathrow passport line last night, I was stood behind Olivier Rochus, the tennis player! I've sometimes wondered what I'd say to a celebrity (define that word how you will - I know who he is!) if I met one, and now I know - absolutely nothing! My main problem was actually deciding whether he was him, or his brother Christophe, who's pretty much identical-looking. If I could have told which one he was sooner (overheard one of the people he was travelling with) I'd have asked him to sign my Aussie Open hat which I had in my coat pocket. Missed opportunities.
posted by Chip : 15:12
4 comments
Comments:
Your average velocity is zero, because as you say, your total displacement is zero... providing you're working it out as (total displacement)/(duration of holiday).
By fiddling with the fuzzy aspects of this, you could probably get a non-zero answer. For example, you could introduce rounding errors if you did something like average(velocity each day).
You might also get some bizzare results by changing the co-ordinate system you're using for your displacement when using the above (ie, if the system is 3D and treats Earth as a sphere, or if it's 2D and assumes it's flat - we usually do the latter when working out travel distances, but we usually don't go all the way around).
You could even throw in the rotation of the earth, the orbit of the earth, the rotation of the galaxy and it's motion through the universe, etc etc etc, if you wanted to be really silly.
And there's always relativity to consider too - velocity is a funtion of time and space, but time and space relative to what?
By fiddling with the fuzzy aspects of this, you could probably get a non-zero answer. For example, you could introduce rounding errors if you did something like average(velocity each day).
You might also get some bizzare results by changing the co-ordinate system you're using for your displacement when using the above (ie, if the system is 3D and treats Earth as a sphere, or if it's 2D and assumes it's flat - we usually do the latter when working out travel distances, but we usually don't go all the way around).
You could even throw in the rotation of the earth, the orbit of the earth, the rotation of the galaxy and it's motion through the universe, etc etc etc, if you wanted to be really silly.
And there's always relativity to consider too - velocity is a funtion of time and space, but time and space relative to what?
That makes 4 others who've agreed with me now, so I think we can safely say it's zero velocity, non-zero speed.
Sarum, yes, I hadn't bothered to say "within the frame of reference of the Earth's surface" - I did apologise to Lint for not having allowed for Hubble expansion...
I think it'll be safe to ignore relativity, at these speeds - I've only done 3 sig figs!
Sarum, yes, I hadn't bothered to say "within the frame of reference of the Earth's surface" - I did apologise to Lint for not having allowed for Hubble expansion...
I think it'll be safe to ignore relativity, at these speeds - I've only done 3 sig figs!
I think that if you are working on euclidean geometry you are right in that your velocity is zero. Or near enough. But if you consider non euclidean geometry on a sphere I think that as you have gone round the planet you do have a velocity. But years since I did non-euclidean geometry so dont trust me. Geek or what.
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