Kw to Hp fomular please.

So THAT'S how you spell it. (Never was much good at German.)

 

PS
This unit (German: Pferdestärke = horse strength) is still commonly used in
Germany and central Europe, although not an lawful unit any more. It is
defined by the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig
as:

1 PS = 735.49875 W

 

Doug Cox said....

DC> ps is metric horsepower. The difference is about 1%.

Anyone here know why ps is used by some magazines and not by others
(they use kilowatts).

Is there an Australian Standard, or some equivalent for metric use
(remember the Metric Board?).

Also, who uses litres/100 km for fuel consumption other than Australia?
And why this particular method? Wouldn't litres/km be a more logical
method? Or wouldn't it?

 

"Martin Taylor" wrote

Ocean liners use tonnes per day at XX knots.

Theo

 

} Also, who uses litres/100 km for fuel consumption other than Australia?

Germany.

--
// Rik Steenwinkel '85 R80ST Skippy bike
// Enschede '91 R100GS/PD The Great Unwashed
// Netherlands ('76 Honda CB250G Bouwpakketje)
// "Far away is only far away '90 K75C Kommutabike
// if you don't go there" '81 MZ TS250/1+LSW Badkuip

 

Ocean liners use tonnes per day at XX knots.

Same as Goldwings, right? <grin>

 

L/100km gives a much easier to read figure (and for a lot of people easier
to understand) figure than L/km.

Eg: 7L/100km, becomes 0.07L/km.

You could possibly use mL/km (70mL/km). But then we buy Petrol in L.

 

We could always use kilometres per litre.

Using 7L/100km, that would be 14.3km/L, or 35ish mpg.

 

Or 41 mpg in Imperial. We don't normally consider US gallons to be any kind
of standard measure in Aus.

Theo

 

I wrote this while I was procrastinating at work:
http://www.xdweb.net/~dibblego/powerconv/

You'll need a JVM version >= 1.2 in your web browser (The default Microsoft
VM in IE will fail).

--
Tony Morris
(BInfTech, Cert 3 I.T., SCJP[1.4], SCJD)
Software Engineer
IBM Australia - Tivoli Security Software
(2003 VTR1000F)

 

*embarrassed*

OOpsies. Been talking to the 'Murricans a bit lately, getting lazy.

 

new group misc.metric-system added

Because the modern metric system is the International System of Units
(SI). Watts are the only SI units of power, with appropriate
prefixes. In fact, for each quantity in SI, there is only one unit
plus prefixes. SI is a "coherent" system of units as that term is
used in metrology, and therefore each of the derived units is some
unitary combination of the base unit. One of each base unit, not some
multiple. (There are also a small list of other units acceptable for
use with SI; Pferdestärke are not on that list.)

PS are not a part of any coherent system. They are not any unitary
combination of base units, but rather defined as 75 kgf·m/s.

In some obsolete coherent systems, you could use 1 kgf·m/s as a unit
of power. However, even that isn't acceptable in SI.

In SI, those "kgf" or kilograms force are also not part of that
system. The only SI units of force are newtons. At least those
obsolete kilograms force, unlike pounds force, do have an official
definition: 1 kgf = 9.80665 N, exactly. Therefore,

1 PS = (75 kgf·m/s)(9.80665 N/kgf) = 735.49875 N·m/s = 735.49875 W

Even the U.S.A. uses L/100 km in onboard displays in automobiles that
have them, and in owner's manuals even for the ones that don't.

It is a more sensble method--for one thing, a bigger number means it
costs you more money, a smaller number is cheaper.

The logical choice would be litres per megametre. Not even any
fractions in normal automotive use, a simple symbol not involving any
numbers (i.e., L/Mm rather than L/100 km, much simpler).

The L/100 km is an anachronism, much like the use of centimetres in a
technical context (but not quite as bad as using cgs units). It's a
silly holdover from pre-SI days. Maybe it made some sense in the old
days when it was legal to call the unit in the denominator a
"hectokilometre" and to use the symbol "L/hkm" but double prefixes
were abolished in SI.

To the sharp-witted reader who will want to point out that litres are
not SI--that's true, but since they were redefined in 1964 as exactly
one cubic decimetre, they have been acceptable for use with SI. This
is one place where there use is very sensible.

Gene Nygaard

 

And then we get to the square meter (or the nano m2) as the obvious
unit of fuel consuption...

 

JRS: In article <tajkaitqjju6sluqe9eg7ihgg4@inews_id.stereo.hq.phicoh.n
et>, seen in Philip Homburg

You may recall that some steam engines collected water from troughs
between the lines. If cars collected fuel similarly, that result would
give the average cross-section of trough needed to supply the car.

Reminds me of a physicist colleague who had Channel Tunnel shares; I
estimated that they were worth one millimetre length of the whole
tunnel, or one square millimetre cross-section extending the whole
distance - very roughly.

 

I would have thought the obvious unit of fuel consumption would have been
the Joule, fuel being an energy source after all.

 

Except the prefixes don't work that way. Yes, 1 L/Mm = 1/1000000000
m², but you can't attach the prefix nano- to "square meters."

1 L/100 km = 10 L/Mm = 0.01 mm² = 10000 µm²

10 L/100 km = 100 L/Mm = 0.1 mm² = 100000 µm²

100 L/100 km = 1000 L/Mm = 1 L/km = 1 mm²

so the sizes aren't that convenient, the numbers don't work out so
good, for using the area measures for fuel consumption.

Gene Nygaard

 

Gene Nygaard <> scribbled the following

I, for one, wish you could attach prefices also in that way. For
example, one microsquare metre would be equal to one square millimetre.
But the standard abbreviations would be ambiguous. Does 1 mm² mean one
square millimetre (like it now does), or one millisquare metre? How
would one write one millisquare millimetre? 1 mmm²?

 

If cars collected fuel similarly, it would take all of fourteen
seconds for some wise arse to produce a lit match...

You should consider getting out more often. Just a thought.

G

 

There is a 'standard' for grouping. What about 1 m(mm)²?

Of course, a square millimetre 'should' be written as 1 (mm)². In math
ab² means a times b times b and not ab times ab.