Why So Many Units?...

[Clifford Heath]

On 22/7/20 5:28 am, Ricketty C wrote:

On Tuesday, July 21, 2020 at 11:52:51 AM UTC-4, Lasse Langwadt Christensen wrote:
tirsdag den 21. juli 2020 kl. 17.18.42 UTC+2 skrev Ricketty C:
On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
For electric cars, the measure is newtons, the force required to
maintain velocity against drag.
Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

But that\'s not what people actually use. You put kWH into your battery,
you get km out. The ratio of those is in newtons.

>>> What really matters is $/mile or €/mile, etc.

The future cost per kW is unknown when you choose a car.

People choose based on full-charge km (can it go where I need to go
without a recharge) and efficiency, in kWH/km (should be n).

Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

What *are* you wittering about? The dimensions of joules/mile is newtons!

joule = newton metre
joule/metre = newton

Clifford Heath

 

[Clifford Heath]

On 22/7/20 5:28 am, Ricketty C wrote:

On Tuesday, July 21, 2020 at 11:52:51 AM UTC-4, Lasse Langwadt Christensen wrote:
tirsdag den 21. juli 2020 kl. 17.18.42 UTC+2 skrev Ricketty C:
On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
For electric cars, the measure is newtons, the force required to
maintain velocity against drag.
Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

But that\'s not what people actually use. You put kWH into your battery,
you get km out. The ratio of those is in newtons.

>>> What really matters is $/mile or €/mile, etc.

The future cost per kW is unknown when you choose a car.

People choose based on full-charge km (can it go where I need to go
without a recharge) and efficiency, in kWH/km (should be n).

Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

What *are* you wittering about? The dimensions of joules/mile is newtons!

joule = newton metre
joule/metre = newton

Clifford Heath

 

[Clifford Heath]

On 22/7/20 4:53 am, John Larkin wrote:

Here\'s my little units program.

https://www.dropbox.com/s/64rg7ko4rc7hhw7/U.zip?dl=0

I could add pressure, but we rarely deal with that.

My modeling language, the Constellation Query Language, has a syntax for
defining fundamental and derived units:

<https://github.com/cjheath/activefacts-examples/blob/master/cql/unit.cql>

If you use it to design a system or database with say, width and height
columns denoted in millimetres, you can query it for width*height in
square feet. The conversion will be supplied - and checked for
conformance. You can\'t query it in hours, for example.

Clifford Heath.

 

[Clifford Heath]

On 22/7/20 4:53 am, John Larkin wrote:

Here\'s my little units program.

https://www.dropbox.com/s/64rg7ko4rc7hhw7/U.zip?dl=0

I could add pressure, but we rarely deal with that.

My modeling language, the Constellation Query Language, has a syntax for
defining fundamental and derived units:

<https://github.com/cjheath/activefacts-examples/blob/master/cql/unit.cql>

If you use it to design a system or database with say, width and height
columns denoted in millimetres, you can query it for width*height in
square feet. The conversion will be supplied - and checked for
conformance. You can\'t query it in hours, for example.

Clifford Heath.

 

[Clifford Heath]

On 22/7/20 4:53 am, John Larkin wrote:

Here\'s my little units program.

https://www.dropbox.com/s/64rg7ko4rc7hhw7/U.zip?dl=0

I could add pressure, but we rarely deal with that.

My modeling language, the Constellation Query Language, has a syntax for
defining fundamental and derived units:

<https://github.com/cjheath/activefacts-examples/blob/master/cql/unit.cql>

If you use it to design a system or database with say, width and height
columns denoted in millimetres, you can query it for width*height in
square feet. The conversion will be supplied - and checked for
conformance. You can\'t query it in hours, for example.

Clifford Heath.

 

[Ricketty C]

On Tuesday, July 21, 2020 at 8:16:30 PM UTC-4, Clifford Heath wrote:

On 22/7/20 5:28 am, Ricketty C wrote:
On Tuesday, July 21, 2020 at 11:52:51 AM UTC-4, Lasse Langwadt Christensen wrote:
tirsdag den 21. juli 2020 kl. 17.18.42 UTC+2 skrev Ricketty C:
On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
For electric cars, the measure is newtons, the force required to
maintain velocity against drag.
Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

But that\'s not what people actually use. You put kWH into your battery,
you get km out. The ratio of those is in newtons.

You are thinking like some sort of scientist or engineer. Lord, no one cares about Newtons! They care about Wh/mi which is exactly what you wrote above. Wh into the battery, miles out, Wh/mi.

Try asking anyone driving or better yet, selling electric cars and see if they know anything about Newtons.

What really matters is $/mile or €/mile, etc.

The future cost per kW is unknown when you choose a car.

Not for me. $0/kWh is zero no matter the scale factor. Besides, electric rates are much less volatile than gas prices.

People choose based on full-charge km (can it go where I need to go
without a recharge) and efficiency, in kWH/km (should be n).


Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.


What *are* you wittering about? The dimensions of joules/mile is newtons!

joule = newton metre
joule/metre = newton

Good for you. You\'ve mastered SI units. Do you have your gold star? Unfortunately you\'re left out of the crowd because no one cares. Wh/mile is the standard measure of the fuel economy of EVs. The US tried with some sort of totally bogus metric called MPGe. I forget exactly how it is calculated, but it attempts to relate EV efficiency to gasoline in a pointless manner. $/mile is what users actually care about. That is less than half the rate of gasoline even taking into account cold climates and non-motive uses of the energy in the battery. I charged at home recently because I haven\'t been making trips with the virus running around. I pay about $0.07 per kWh which nets me around $0.02 per mile summer, $0.03 per mile in winter. Gasoline runs me around $0.10 per mile with the current low prices of gasoline. Even a hybrid will run $0.04 or $0.05 per mile.

Yeah, I\'m sure Tesla can tell you all about the Newtons of their cars.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

[Ricketty C]

On Tuesday, July 21, 2020 at 8:16:30 PM UTC-4, Clifford Heath wrote:

On 22/7/20 5:28 am, Ricketty C wrote:
On Tuesday, July 21, 2020 at 11:52:51 AM UTC-4, Lasse Langwadt Christensen wrote:
tirsdag den 21. juli 2020 kl. 17.18.42 UTC+2 skrev Ricketty C:
On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
For electric cars, the measure is newtons, the force required to
maintain velocity against drag.
Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

But that\'s not what people actually use. You put kWH into your battery,
you get km out. The ratio of those is in newtons.

You are thinking like some sort of scientist or engineer. Lord, no one cares about Newtons! They care about Wh/mi which is exactly what you wrote above. Wh into the battery, miles out, Wh/mi.

Try asking anyone driving or better yet, selling electric cars and see if they know anything about Newtons.

What really matters is $/mile or €/mile, etc.

The future cost per kW is unknown when you choose a car.

Not for me. $0/kWh is zero no matter the scale factor. Besides, electric rates are much less volatile than gas prices.

People choose based on full-charge km (can it go where I need to go
without a recharge) and efficiency, in kWH/km (should be n).


Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.


What *are* you wittering about? The dimensions of joules/mile is newtons!

joule = newton metre
joule/metre = newton

Good for you. You\'ve mastered SI units. Do you have your gold star? Unfortunately you\'re left out of the crowd because no one cares. Wh/mile is the standard measure of the fuel economy of EVs. The US tried with some sort of totally bogus metric called MPGe. I forget exactly how it is calculated, but it attempts to relate EV efficiency to gasoline in a pointless manner. $/mile is what users actually care about. That is less than half the rate of gasoline even taking into account cold climates and non-motive uses of the energy in the battery. I charged at home recently because I haven\'t been making trips with the virus running around. I pay about $0.07 per kWh which nets me around $0.02 per mile summer, $0.03 per mile in winter. Gasoline runs me around $0.10 per mile with the current low prices of gasoline. Even a hybrid will run $0.04 or $0.05 per mile.

Yeah, I\'m sure Tesla can tell you all about the Newtons of their cars.

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209

 

[whit3rd]

On Sunday, July 19, 2020 at 11:23:22 PM UTC-7, Ricketty C wrote:
> I thought the point of SI was to unify the use of units so everyone could speak the same language?

....[half dozen units for pressure]

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

Sometimes, you just want a unit that fits the problem well, like Smoots for fraternity distance
measure.

I\'ve been experimenting (in the era of days-between-shaves and hiding behind a mask)
with shaving products. There\'s a goo called \'brushless shave cream\' that works well
in a shower, because you can flush your face with water and use a washcloth to
get it all off.

The proper quantity of the slime to use for a shave is between two garden slugs, and
one-quarter banana slug.

 

[whit3rd]

On Sunday, July 19, 2020 at 11:23:22 PM UTC-7, Ricketty C wrote:
> I thought the point of SI was to unify the use of units so everyone could speak the same language?

....[half dozen units for pressure]

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

Sometimes, you just want a unit that fits the problem well, like Smoots for fraternity distance
measure.

I\'ve been experimenting (in the era of days-between-shaves and hiding behind a mask)
with shaving products. There\'s a goo called \'brushless shave cream\' that works well
in a shower, because you can flush your face with water and use a washcloth to
get it all off.

The proper quantity of the slime to use for a shave is between two garden slugs, and
one-quarter banana slug.

 

[whit3rd]

On Sunday, July 19, 2020 at 11:23:22 PM UTC-7, Ricketty C wrote:
> I thought the point of SI was to unify the use of units so everyone could speak the same language?

....[half dozen units for pressure]

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

Sometimes, you just want a unit that fits the problem well, like Smoots for fraternity distance
measure.

I\'ve been experimenting (in the era of days-between-shaves and hiding behind a mask)
with shaving products. There\'s a goo called \'brushless shave cream\' that works well
in a shower, because you can flush your face with water and use a washcloth to
get it all off.

The proper quantity of the slime to use for a shave is between two garden slugs, and
one-quarter banana slug.

 

[Cydrome Leader]

Ricketty C <gnuarm.deletethisbit@gmail.com> wrote:

On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
On 20/7/20 8:00 pm, Piotr Wyderski wrote:
Ricketty C wrote:

I thought the point of SI was to unify the use of units so everyone
could speak the same language?

People cannot even agree what a ton is.

WTF?!?? Why have multiple units like this?

Do you express fuel consumption of cars in square meters, as it should
have always been? This is the cross-section area of the virtual stream
of fuel running along your car when you are driving. Self-normalised,
doesn\'t need any \"per 100km\".

It\'s the cross-section area of a long thread of fuel that you car can
use to follow without losing speed. Ours does better than 0.1mm^2 only
on the highway, approximately a 0.25mm diameter thread of fuel. That
doesn\'t seem like much.

For electric cars, the measure is newtons, the force required to
maintain velocity against drag. Even for gasoline cars, that would be
more instructive, with a separate efficiency measure for the engine.

Clifford Heath.

Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

What really matters is $/mile or ???/mile, etc. Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

A measure that would be similar to your newton number would simply be kW. This will relate more to useful units that can be used to find energy consumption and cost. I love mashing the accelerator and watching the kW meter run up to 400 in my car.

Oh yeah, my car needs 1.25 amps at 240 V to run on the highway at 60 MPH (97 kph) which will require a wire of about 20 gauge which is about 0.5 mm^2 cross section, 0.8 mm diameter.

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

 

[Cydrome Leader]

Ricketty C <gnuarm.deletethisbit@gmail.com> wrote:

On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
On 20/7/20 8:00 pm, Piotr Wyderski wrote:
Ricketty C wrote:

I thought the point of SI was to unify the use of units so everyone
could speak the same language?

People cannot even agree what a ton is.

WTF?!?? Why have multiple units like this?

Do you express fuel consumption of cars in square meters, as it should
have always been? This is the cross-section area of the virtual stream
of fuel running along your car when you are driving. Self-normalised,
doesn\'t need any \"per 100km\".

It\'s the cross-section area of a long thread of fuel that you car can
use to follow without losing speed. Ours does better than 0.1mm^2 only
on the highway, approximately a 0.25mm diameter thread of fuel. That
doesn\'t seem like much.

For electric cars, the measure is newtons, the force required to
maintain velocity against drag. Even for gasoline cars, that would be
more instructive, with a separate efficiency measure for the engine.

Clifford Heath.

Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

What really matters is $/mile or ???/mile, etc. Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

A measure that would be similar to your newton number would simply be kW. This will relate more to useful units that can be used to find energy consumption and cost. I love mashing the accelerator and watching the kW meter run up to 400 in my car.

Oh yeah, my car needs 1.25 amps at 240 V to run on the highway at 60 MPH (97 kph) which will require a wire of about 20 gauge which is about 0.5 mm^2 cross section, 0.8 mm diameter.

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

 

[Cydrome Leader]

Ricketty C <gnuarm.deletethisbit@gmail.com> wrote:

On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
On 20/7/20 8:00 pm, Piotr Wyderski wrote:
Ricketty C wrote:

I thought the point of SI was to unify the use of units so everyone
could speak the same language?

People cannot even agree what a ton is.

WTF?!?? Why have multiple units like this?

Do you express fuel consumption of cars in square meters, as it should
have always been? This is the cross-section area of the virtual stream
of fuel running along your car when you are driving. Self-normalised,
doesn\'t need any \"per 100km\".

It\'s the cross-section area of a long thread of fuel that you car can
use to follow without losing speed. Ours does better than 0.1mm^2 only
on the highway, approximately a 0.25mm diameter thread of fuel. That
doesn\'t seem like much.

For electric cars, the measure is newtons, the force required to
maintain velocity against drag. Even for gasoline cars, that would be
more instructive, with a separate efficiency measure for the engine.

Clifford Heath.

Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

What really matters is $/mile or ???/mile, etc. Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

A measure that would be similar to your newton number would simply be kW. This will relate more to useful units that can be used to find energy consumption and cost. I love mashing the accelerator and watching the kW meter run up to 400 in my car.

Oh yeah, my car needs 1.25 amps at 240 V to run on the highway at 60 MPH (97 kph) which will require a wire of about 20 gauge which is about 0.5 mm^2 cross section, 0.8 mm diameter.

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

 

[Mikko OH2HVJ]

Cydrome Leader <presence@MUNGEpanix.com> writes:

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

The same as for most other energy flows - kW.

--
mikko

 

[Mikko OH2HVJ]

Cydrome Leader <presence@MUNGEpanix.com> writes:

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

The same as for most other energy flows - kW.

--
mikko

 

[Mikko OH2HVJ]

Cydrome Leader <presence@MUNGEpanix.com> writes:

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

The same as for most other energy flows - kW.

--
mikko

 

[Mike Coon]

In article <fb08d919-9189-4ef8-80f1-8583f7bae69do@googlegroups.com>,
whit3rd@gmail.com says...

I\'ve been experimenting (in the era of days-between-shaves and hiding behind a mask)
with shaving products. There\'s a goo called \'brushless shave cream\' that works well
in a shower, because you can flush your face with water and use a washcloth to
get it all off.

The proper quantity of the slime to use for a shave is between two garden slugs, and
one-quarter banana slug.

That matches the assumption that toothpaste is intended to be squeezed
out for the length of the bristled part of the brush. Thus if the tube
has a wide mouth everyone will use more toothpaste and thus buy more...

 

[Mike Coon]

In article <a784766d-74a6-4d21-a118-aa0006c8b6bao@googlegroups.com>,
gnuarm.deletethisbit@gmail.com says...

You are thinking like some sort of scientist or engineer. Lord, no

one cares about Newtons! They care about Wh/mi which is exactly what
you wrote above. Wh into the battery, miles out, Wh/mi.

Strangely, lifejacket buoyancy is specified in newtons. Sometimes they
even have dinky batteries...

 

[Mike Coon]

In article <fb08d919-9189-4ef8-80f1-8583f7bae69do@googlegroups.com>,
whit3rd@gmail.com says...

I\'ve been experimenting (in the era of days-between-shaves and hiding behind a mask)
with shaving products. There\'s a goo called \'brushless shave cream\' that works well
in a shower, because you can flush your face with water and use a washcloth to
get it all off.

The proper quantity of the slime to use for a shave is between two garden slugs, and
one-quarter banana slug.

That matches the assumption that toothpaste is intended to be squeezed
out for the length of the bristled part of the brush. Thus if the tube
has a wide mouth everyone will use more toothpaste and thus buy more...

 

[Jasen Betts]

On 2020-07-22, Cydrome Leader <presence@MUNGEpanix.com> wrote:

Ricketty C <gnuarm.deletethisbit@gmail.com> wrote:
On Tuesday, July 21, 2020 at 3:47:40 AM UTC-4, Clifford Heath wrote:
On 20/7/20 8:00 pm, Piotr Wyderski wrote:
Ricketty C wrote:

I thought the point of SI was to unify the use of units so everyone
could speak the same language?

People cannot even agree what a ton is.

WTF?!?? Why have multiple units like this?

Do you express fuel consumption of cars in square meters, as it should
have always been? This is the cross-section area of the virtual stream
of fuel running along your car when you are driving. Self-normalised,
doesn\'t need any \"per 100km\".

It\'s the cross-section area of a long thread of fuel that you car can
use to follow without losing speed. Ours does better than 0.1mm^2 only
on the highway, approximately a 0.25mm diameter thread of fuel. That
doesn\'t seem like much.

For electric cars, the measure is newtons, the force required to
maintain velocity against drag. Even for gasoline cars, that would be
more instructive, with a separate efficiency measure for the engine.

Clifford Heath.

Newton is not useful since it will vary hugely over speed and only be useful to compare cars directly while saying nothing about what you really care about, cost.

What really matters is $/mile or ???/mile, etc. Since the cost of electricity varies widely the energy per mile is useful as joules/mile or more commonly, even if not SI, kWh/mi. Of course these numbers will be related to driving patterns, but not the huge, direct impact that newtons suffer, just the same smaller effect we are used to with MPG.

A measure that would be similar to your newton number would simply be kW. This will relate more to useful units that can be used to find energy consumption and cost. I love mashing the accelerator and watching the kW meter run up to 400 in my car.

Oh yeah, my car needs 1.25 amps at 240 V to run on the highway at 60 MPH (97 kph) which will require a wire of about 20 gauge which is about 0.5 mm^2 cross section, 0.8 mm diameter.

What\'s the unit for heat rejection as in aircondition outside the US? We
use BTUs and Tons. Never seen a conversion chart or found a spec sheet for
aircoditioners not meant for the north american market.

Kilowatts.

eg: https://www.harveynorman.co.nz/event/triple-airpoints/kelvinator-split-cycle-air-conditioner-heat-pump-en-2.html

--
Jasen.