WTF Bites
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@scholrlea If I had to guess, I'd guess he meant 2.5 l/100km. Other good guesses:
2.5 l/km would be very bad for a gasoline-powered car
2.5 l/km would be very good for a gasoline-powered battle tank
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@anotherusername Those are better, but 16 mpg is still pretty crappy for a modern car. Most non-SUVs get in the mid-upper 20s or low 30s.
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@benjamin-hall said in WTF Bites:
@anotherusername Those are better, but 16 mpg is still pretty crappy for a modern car. Most non-SUVs get in the mid-upper 20s or low 30s.
My Focus, which is quite a big car, is managing to average 47 MPG. The new Ecoboost engine is astonishingly efficient. Especially when compared to my last car which got about 12 MPG.
@anotherusername said in WTF Bites:
2.5 l/km would be very good for a gasoline-powered battle tank
The M1 Abrams looks like it gets 4.4 l/km (0.53 MPG), so 2.5 sounds great for a tank.
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@cursorkeys Yeah. I have a lead foot and an older (2010) Honda Civic, and I get 25-ish mostly city MPG.
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@cursorkeys said in WTF Bites:
My Focus, which is quite a big car
European car owner spotted !
N.B.: Focus is called a compact car in America
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@timebandit said in WTF Bites:
@cursorkeys said in WTF Bites:
My Focus, which is quite a big car
European car owner spotted !
N.B.: Focus is called a compact car in America
Guilty, I'm surprised it's compact though. Damn thing won't fit in my garage. I wonder what a Smart would be classed as.
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@cursorkeys said in WTF Bites:
Damn thing won't fit in my garage
Then, what you have is what we call a shed :face_with_stuck-out_tongue_winking_eye:
@cursorkeys said in WTF Bites:
I wonder what a Smart would be classed as
A deathtrap
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@cursorkeys You may also be falling foul of Americans having a different gallon to us Right-Pondians.
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@benjamin-hall said in WTF Bites:
16 mpg is still pretty crappy
Not sure how you calculated that. Maybe recheck your maths?
edit: if you're feeling especially lazy, you can just unit and let google maths it:
It knows that there's an inverse relationship and calculates the conversion properly.
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@anotherusername
Not his math error, it's @ScholRLEA's upthread which he then just applied an order of magnitude correction to.Looks like the original error is in the conversion from km/L to m/gal... the conversion should be:
0.4 km/L * 3.9L/gal * 0.62 miles/km = 0.9672 mpg
But what he actually did was 0.4km/L / 4L/gal / 0.62 miles/km. Basically just got the divisors flipped from the inline simplification he did.
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@cursorkeys said in WTF Bites:
@timebandit said in WTF Bites:
@cursorkeys said in WTF Bites:
My Focus, which is quite a big car
European car owner spotted !
N.B.: Focus is called a compact car in America
Guilty, I'm surprised it's compact though. Damn thing won't fit in my garage. I wonder what a Smart would be classed as.
A roller skate.
As crazy as it sounds to the sane parts of the world, I am pretty sure that your typical American would sooner be seen driving one of these:
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@scholrlea Why did you post a picture of a Smart car, shouldn't it be something else?
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@izzion you're right. Although his result was 0.16 MPG, not 16 MPG, and omitting the decimal point seems to me like it's more of an additional error than it is an attempt at "correction".
@scholrlea said in WTF Bites:
Let's work that out for My Fellow Murkins
1 / (2.5 L/km) = 0.4 km/L == (0.4L * 3.9gal.) / 0.62 miles/km == 0.1 gal. / 0.62 miles = 0.16 mpg
Let's work it out properly now.
And eliminate the weird double flip thing you did in the middle where you somehow ended up with gallons per miles instead of miles per gallon. You were correct up to the point where you had distance divided by volume, so I don't know how or why you ended up with volume divided by distance at any point in the calculation.edit: or, yes, a factor of 0.621371 mi / 1 km would work too. I like to have a whole unit for the larger unit though, so that the value of the smaller unit is >1.
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@anotherusername
Well, right. Because @Benjamin-Hall was then saying, maybe 2.5L/100km would be sensible (instead of the 2.5L/km that was originally thrown around), and so he took the previously provided (incorrect) value for 2.5L/km, multiplied by 100, and Robert's your mother's brother.
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@izzion ah, I gotcha now.
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@anotherusername said in WTF Bites:
@izzion you're right. Although his result was 0.16 MPG, not 16 MPG, and omitting the decimal point seems to me like it's more of an additional error than it is an attempt at "correction".
@scholrlea said in WTF Bites:
Let's work that out for My Fellow Murkins
1 / (2.5 L/km) = 0.4 km/L == (0.4L * 3.9gal.) / 0.62 miles/km == 0.1 gal. / 0.62 miles = 0.16 mpg
Let's work it out properly now.
This is why
we can't have nice thingsI never did well at chemistry. Sorry.
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2.5L/km
Found the engine that does exactly that
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@anotherusername That was after multiplying by 100 (going from L/km to L/100km).
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@scholrlea said in WTF Bites:
@anotherusername said in WTF Bites:
@izzion you're right. Although his result was 0.16 MPG, not 16 MPG, and omitting the decimal point seems to me like it's more of an additional error than it is an attempt at "correction".
@scholrlea said in WTF Bites:
Let's work that out for My Fellow Murkins
1 / (2.5 L/km) = 0.4 km/L == (0.4L * 3.9gal.) / 0.62 miles/km == 0.1 gal. / 0.62 miles = 0.16 mpg
Let's work it out properly now.
This is why
we can't have nice thingsI never did well at chemistry. Sorry.The "multiply by fractions that are equal to 1" method came as a bit of a revelation to me. I never had that much trouble with the more intuitive method that you gave an example of (this is my conversion factor, I multiply/divide by it and it converts in the proper direction). But using fractions does put everything down on your paper and makes it easier to double-check that you're getting the right result, and now that I'm really rusty, it can be a good way to make sure I'm not making stupid mistakes.
Then you just have to make sure that your fraction is really 1 (i.e. top and bottom are equal) and that the units cancel properly as algebra says that they should. (If they don't, you flip the fraction upside down.)
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@anotherusername said in WTF Bites:
@scholrlea said in WTF Bites:
@anotherusername said in WTF Bites:
@izzion you're right. Although his result was 0.16 MPG, not 16 MPG, and omitting the decimal point seems to me like it's more of an additional error than it is an attempt at "correction".
@scholrlea said in WTF Bites:
Let's work that out for My Fellow Murkins
1 / (2.5 L/km) = 0.4 km/L == (0.4L * 3.9gal.) / 0.62 miles/km == 0.1 gal. / 0.62 miles = 0.16 mpg
Let's work it out properly now.
This is why
we can't have nice thingsI never did well at chemistry. Sorry.The "multiply by fractions that are equal to 1" method came as a bit of a revelation to me. I never had that much trouble with the more intuitive method that you gave an example of (this is my conversion factor, I multiply/divide by it and it converts in the proper direction). But using fractions does put everything down on your paper and makes it easier to double-check that you're getting the right result, and now that I'm really rusty, it can be a good way to make sure I'm not making stupid mistakes.
Then you just have to make sure that your fraction is really 1 (i.e. top and bottom are equal) and that the units cancel properly as algebra says that they should. (If they don't, you flip the fraction upside down.)
You wouldn't believe the difficulties my pupils have when I try to tell them that it's not a good idea to simply insert anything and everything into a calculator first. Especially when using radians. ("No, when the angular velocity is π/3 1/s you put that into your formula and not 1.0472 1/s! Because the task afterwards asks you what the elongation is after 3 seconds which yields just π as a result and the sine thereof is just zero! And NOT -7.34E-6!)
And then they look at me like I'm a genius when I do the calculations in my head because I simplify first and only afterwards do the rest of the calculations.
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π/3 1/s
Ah yes... radians per second...
Radians being a unitless unit still weirds me out sometimes, apparently...
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@anotherusername said in WTF Bites:
π/3 1/s
Ah yes... radians per second...
Radians being a unitless unit still weirds me out sometimes, apparently...
My physics textbook (Tipler) also allowed rad/s. But you'd better remember that it's actually not a unit or you'd get problems with the trigonometric functions ;)
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you'd better remember that it's actually not a unit or you'd get problems
Yeah, I was about to say, good luck trying to simplify it out if you do.
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@anotherusername Then again,
sin(90°)
is also perfectly fine to write, soooo...
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@rhywden at least there, you have a conversion factor to use: π/180°. Degrees cancel and you're left with radians.
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@rhywden I require my physics students to do the symbolic algebra before putting in any numbers. They hate it. Too used to just putting in numbers everywhere and accepting whatever garbage the calculator spits out (and having serious rounding errors everywhere).
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My physics textbook (Tipler) also allowed rad/s
I'm used to s-1.
You could write Hz to confuse people.
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This post is deleted!
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@cursorkeys You may also be falling foul of Americans having a different gallon to us Right-Pondians.
I hadn't even thought of that. You're quite right, so my car is 39 MPG (US)
My physics textbook (Tipler) also allowed rad/s
I'm used to s-1.
You could write Hz to confuse people.
Or be properly old-school and use CPS (cycles per second).
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You wouldn't believe the difficulties my pupils have when I try to tell them that it's not a good idea to simply insert anything and everything into a calculator first. Especially when using radians. ("No, when the angular velocity is π/3 1/s you put that into your formula and not 1.0472 1/s! Because the task afterwards asks you what the elongation is after 3 seconds which yields just π as a result and the sine thereof is just zero! And NOT -7.34E-6!)
And then they look at me like I'm a genius when I do the calculations in my head because I simplify first and only afterwards do the rest of the calculations.
Don't forget π/3 is an easy one too, as are π/4 and π/6
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@cursorkeys said in WTF Bites:
Guilty, I'm surprised it's compact though. Damn thing won't fit in my garage.
Yuck. I test drove one before we bought our current Fusion and it was uncomfortable to sit in, it was so small.
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@timebandit said in WTF Bites:
@cursorkeys said in WTF Bites:
" I wonder what a Smart would be classed as"A
deathtrapgolf cart
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@boomzilla I don't think any respectable golf course would allow that
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@hungrier Of course not. There's not even a place to put your clubs!
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@boomzilla And no beer holder
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@hungrier
Though I do think an actual golf cart would probably be safer to operate on city streets than a Smart.And yes, I do have experience with people who operate actual golf carts on city streets (albeit the residential area super-low-speed-limit city streets and not the major cross-city thoroughfares).
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@boomzilla said in WTF Bites:
@cursorkeys said in WTF Bites:
Guilty, I'm surprised it's compact though. Damn thing won't fit in my garage.
Yuck. I test drove one before we bought our current Fusion and it was uncomfortable to sit in, it was so small.
I was a little dismayed after I bought it, the MK3 Focus is noticeably bigger than the MK1 Focus, I do have trouble getting it in the bays at train stations and similar where the old MK1 fitted with room to spare.
In the US I've only been to New England but I noticed all the parking bays were much bigger, which was nice. I hired a Chrysler Town and Country when I was there which to be honest felt like driving a minibus. When I got to the hire place I asked if I could upgrade to the biggest thing they had, the guy showed me a Ford truck thing which looked like it could tow an artic...I settled for the Town and Country as the biggest thing I thought I could safely drive, he thought that was hilarious.
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@cursorkeys said in WTF Bites:
I noticed all the parking bays were much bigger
You need some room for the passengers to get in and out of the car
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@anotherusername said in WTF Bites:
π/3 1/s
Ah yes... radians per second...
Radians being a unitless unit still weirds me out sometimes, apparently...
My physics textbook (Tipler) also allowed rad/s. But you'd better remember that it's actually not a unit or you'd get problems with the trigonometric functions ;)
It is a unit, but using it will get you another whole set of problems.
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Status: Attempting to undelete shit I deleted on accident from the NAS...
WTH I can open it from the virtual folder thing, why can't I copy it?!?!? Gah!
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@anotherusername said in WTF Bites:
π/3 1/s
Ah yes... radians per second...
Radians being a unitless unit still weirds me out sometimes, apparently...
My physics textbook (Tipler) also allowed rad/s. But you'd better remember that it's actually not a unit or you'd get problems with the trigonometric functions ;)
It is a unit, but using it will get you another whole set of problems.
I think you meant: https://en.wikipedia.org/wiki/Radian
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@cursorkeys said in WTF Bites:
@boomzilla said in WTF Bites:
@cursorkeys said in WTF Bites:
Guilty, I'm surprised it's compact though. Damn thing won't fit in my garage.
Yuck. I test drove one before we bought our current Fusion and it was uncomfortable to sit in, it was so small.
I was a little dismayed after I bought it, the MK3 Focus is noticeably bigger than the MK1 Focus, I do have trouble getting it in the bays at train stations and similar where the old MK1 fitted with room to spare.
In the US I've only been to New England but I noticed all the parking bays were much bigger, which was nice. I hired a Chrysler Town and Country when I was there which to be honest felt like driving a minibus. When I got to the hire place I asked if I could upgrade to the biggest thing they had, the guy showed me a Ford truck thing which looked like it could tow an artic...I settled for the Town and Country as the biggest thing I thought I could safely drive, he thought that was hilarious.I test drove my grandmother's minivan (old Plymouth Voyager) after recharging the batteries for her, and I felt like I was driving a Hot Wheels mini. It turned in less than a quarter mile and actually fit inside parking spaces!
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@Rhywden No, I meant what I linked.
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@scholrlea said in WTF Bites:
"What is a String used for?"
Duh. EVERYTHING!
No, that's Tcl.
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@cursorkeys said in WTF Bites:
I wonder what a Smart would be classed as.
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@Rhywden No, I meant what I linked.
I was somewhere last weekend that was averaging 87 uSv/s. Hope I've done the maths wrong because that's a quite scary dose if we were there for 7 hours.
Edit: Radium dust from broken aircraft instruments, nothing sinister.
Edit2: Calculated it wrong, we basically got a years background dose. Not really worth worrying about.
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You could write Hz to confuse people.
And that would be wrong. While yes, you can view waves in terms of angular velocities and so on, the frequency of a wave and the associated angular velocity are very much not the same thing. It's easiest to leave the radians in as a unit as much as possible on the physics side to stop that sort of nonsense…
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@timebandit said in WTF Bites:
@cursorkeys said in WTF Bites:
I noticed all the parking bays were much bigger
passengers
HEY! I resemble that remark.
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Trying to figure out if the clang version Apple ships with OS X (well, with XCode 9.1) is up to date:
$ clang --version Apple LLVM version 9.0.0 (clang-900.0.38)
Um, what's that? Considering that afaict the latest stable clang version is 5.0, that's got to be pretty new. Like, right from the future.
Ok, so according to the LLVM blog clang has OpenMP support since 2015 (version 3.8), let's try that:
clang: error: unsupported option '-fopenmp'
Yes, of course.