Topic 'Re: Weights and measures' in forum '' - dslreports.com

Re: Weights and measures

Fri, 16 Nov 2012 10:21:32 EDT

chamberc posted :

said by talz13:

It is always a gallon of gas, but due to temperature fluctuations, it may not be the same mass due to higher densities in cold temperatures, and lower densities in warmer temperatures.

Which is why Costco pumps have a label on them now stating that they sell gas by volume not energy content. Some ambulance chaser thought they could win a lawsuit because the pumps weren't temperature compensating.

Take E85. A gallon has 1/3 less energy content, so therefore it takes 1/3 more E85 to go the same distance as gas.

I always laugh when I see people filling up with E85 thinking they're paying less, and yes, I ran two tanks of the crap to confirm. My gas mileage dropped from 12 mpg to 8.

Re: Weights and measures

Thu, 15 Nov 2012 10:37:44 EDT

DataRiker posted : it is arbitrary until you once again qualify "in a vacuum"

Science is very particular about details

Re: Weights and measures

Thu, 15 Nov 2012 10:35:49 EDT

anon posted : >good example, a meter is how long it takes for light to travel in 1/299 792 458 of a second.

Yeah, that doesn't sound arbitrary or anything.

Re: Weights and measures

Thu, 15 Nov 2012 10:27:13 EDT

DataRiker posted : Force is defined using mass.

If you use pound in science, you will be immediately asked to clarify if you mean force or mass.

Re: Weights and measures

Thu, 15 Nov 2012 10:24:30 EDT

cowboyro posted :

said by BonezX:

said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

»en.wikipedia.org/wiki/Slug_%28mass%29
»en.wikipedia.org/wiki/Normal_force

might want to also look outside the united states of stuck in the past, if you did calculations in the scientific community, or about ~90% of the countries in the world in lb you would be laughed at.

The pound is the official unit for mass. Not force, mass.
The slug is a derived unit that makes the 1:1 translation between units of time, length and force so that F=m*a

Re: Weights and measures

Thu, 15 Nov 2012 10:21:34 EDT

MaynardKrebs posted :

said by cdru:

.......That gives you the equivalent additional energy as an extra 52.8mL at the baseline temp, or a 5.28% advantage. Putting that in terms of units Americans would understand, that's like getting an extra 7/8ths of a cup of gas per gallon.

52ml is roughly 20% of a standard 8oz./250ml 'cup', or approximately 2 ounces or 1/4 cup.

Anyone have any idea what the typical temperature of gasoline is when it's held in above ground tanks at the refiners terminal, and how much hat temperature varies though the year in different climatic zones?

Re: Weights and measures

Thu, 15 Nov 2012 10:17:09 EDT

DataRiker posted :

said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

This is a rather silly point since force is defined using mass.

When you understand your circular reasoning get back to me.

Re: Weights and measures

Thu, 15 Nov 2012 10:05:30 EDT

cdru posted :

said by MaynardKrebs:

You *might* gain some energy content advantage is you filled up in the winter just after the underground tanks were replenished, if the tanker had traveled 200 miles in -20F weather and chilled the gasoline.

To quantify that amount...

Gasoline expands about 1.2ml per liter per 1 degree C increase in temperature. The variation between -20F and the baseline 15C is approximately 44C. That gives you the equivalent additional energy as an extra 52.8mL at the baseline temp, or a 5.28% advantage. Putting that in terms of units Americans would understand, that's like getting an extra 7/8ths of a cup of gas per gallon.

It usually averages out though for non-ATC pumps. Because for tanks that you might get at -20F, you may also get gas at 80 or 90 degrees and you lose the advantage.

Re: Weights and measures

Thu, 15 Nov 2012 09:34:34 EDT

BonezX posted :

said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

Re: Weights and measures

Thu, 15 Nov 2012 09:27:33 EDT

cowboyro posted :

said by BonezX:

said by cowboyro:

said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.

LB is a measurement of force(weight is called the normal force of an object fyi), the imperial measurement of mass is the slug.

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

Re: Weights and measures

Thu, 15 Nov 2012 08:53:25 EDT

BonezX posted :

said by cowboyro:

said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.

LB is a measurement of force(weight is called the normal force of an object fyi), the imperial measurement of mass is the slug.

Re: Weights and measures

Wed, 14 Nov 2012 23:10:35 EDT

DataRiker posted : Weight is a force, so if your going to use some subjective context for reference (which is unwise) lb force would be more fitting.

Since neither of you used "pound-force" [lbf] or "pound-mass" [lbm], any argument that one definition is more correct than the other is extremely silly.

The unqualified "pound" should never ever be used in anything but the most informal oral conversations.

Re: Weights and measures

Wed, 14 Nov 2012 22:58:12 EDT

cowboyro posted :

said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.

Re: Weights and measures

Wed, 14 Nov 2012 22:42:24 EDT

DataRiker posted : The term pound can refer to a mass or a force. The unqualified term "pound" is ambiguous.

If one wishes to be unambiguous you can refer to either a pound-mass or pound-force.

Or just use the SI units since they are designed to be unambiguous.

Re: Weights and measures

Wed, 14 Nov 2012 22:25:02 EDT

cowboyro posted :

said by BonezX:

i love when people apply Imperial theory to SI units, it just makes my day.
an LB is a force

Actually a lb is a unit for MASS not for force.
1lb is defined as 0.45359237 kilograms.

said by BonezX:

Imperial units are arbitrary, where SI units are standardized.

They are not arbitrary at all. Not any more than SI units. There is a strong, well-defined relationship between imperial and SI units.

Re: Weights and measures

Wed, 14 Nov 2012 21:20:46 EDT

BonezX posted :

said by BF69:

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

Actually the moon's gravity is 1/6 that of Earth so a kilogram on Earth would be 1/6 kilogram on the moon.

i love when people apply Imperial theory to SI units, it just makes my day.

an LB is a force(F=M*A), not a mass, weight is a measurement of force, a slug is a mass not a force
a Newton is a force, not a mass, a kg is a mass not a force.

gravity is calculated at 9.8m/s^2, or 32.15ft/s^2

Imperial units are arbitrary, where SI units are standardized.

good example, a meter is how long it takes for light to travel in 1/299 792 458 of a second.

Re: Weights and measures

Wed, 14 Nov 2012 20:02:02 EDT

DataRiker posted :

said by BF69:

Actually the moon's gravity is 1/6 that of Earth so a kilogram on Earth would be 1/6 kilogram on the moon.

Also technically gravity is slightly stronger at the north pole so a kilogram at the equator would be slightly more than a kilogram at the north pole.

You don't even know the first grade definition of mass....

Re: Weights and measures

Wed, 14 Nov 2012 17:28:39 EDT

anon posted : Nope. Grams and their variants are a measure of the amount of mass an object has. Pounds is a measure of the force of gravity over an object. An object will weigh less on the moon, but will still have the same mass. Does no one take science class these days?

Re: Weights and measures

Wed, 14 Nov 2012 17:02:21 EDT

cowboyro posted :

said by prairiesky:

there is a mass pound, but the general term lb/pound refers to a weight, which is a force not a mass.

No they are not.
lbs are imperial units for mass, kilograms are [SI] units for mass.

Re: Weights and measures

Wed, 14 Nov 2012 16:03:52 EDT

prairiesky posted : there is a mass pound, but the general term lb/pound refers to a weight, which is a force not a mass. Because the mass pound and the force pound (weight) are so closely labeled, Grams are much preferred for use of mass.

Re: Weights and measures

Wed, 14 Nov 2012 15:35:57 EDT

koolman2 posted : Pounds and grams both measure the same thing: mass. 5 kg = 11.023 lbs on Earth as well as the moon.

Re: Weights and measures

Wed, 14 Nov 2012 15:20:58 EDT

prairiesky posted :

said by BF69:

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

??
You're confusing lbs with KG, kg's don't change as a result of gravity.

Data is completely different. Data is simply a count. Like, I have 3 apples. All of our measuring devices are subject to physical variations such as temperatures, pressures etc. The units are also defined by substances, for instance, 1 KG is 1 L of water. 1 L doesn't change based on external forces, but the amount of water contained within that space sure does hence the definition of 1 KG being 1 L / water needs contraints on the variables that affect it.

Data is simply a count. I transfered 3 apples, either you did or you didn't, there are no external forces that change that count. it's either right or it's wrong

Re: Weights and measures

Wed, 14 Nov 2012 14:58:03 EDT

cowboyro posted :

said by BF69:

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

The mass is a property of an object. It does not change.(*)
Weight on the other side is the force exerted by gravitation. We conveniently refer to mass as weight as on Earth the difference is negligible for most practical purposes. We are actually measuring the weight force and translating into "the mass that produces the weight on Earth".
-----
(*)exception for objects that absorb or release energy in nuclear fusion or fission reactions.

Re: Weights and measures

Wed, 14 Nov 2012 13:37:34 EDT

darkcrucible posted : This is not correct. A kilogram is a measurement of mass. That is, how much stuff there is in something. A kilogram of carbon will still be a kilogram on the moon, the north pole or anywhere else. What you're thinking of is weight which is not the same as mass.

For example, there are 6.03x10^23 atoms of carbon in 12 grams of carbon. Just because you take that carbon to the moon doesn't suddenly mean there are 1.005x10^23 atoms of carbon (2 gram of C).

Re: Weights and measures

Wed, 14 Nov 2012 13:31:37 EDT

InvalidError posted :

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

A kilogram may be a kilogram and a liter may be a liter but the calibration of measurement instruments can drift over time due to temperature, humidity, wear, aging, corrosion, contamination, etc.

This is why physical quantity measurement equipment needs to be periodically inspected and calibrated.

Re: 50Mb vs 105Mb technical/install differences?

Wed, 14 Nov 2012 13:23:31 EDT

Petermjjh posted : Nope a kilogram is a kilogram no matter what.

However acceleration due to gravity is different on the moon than on Earth. You are thinking of weight which is measured in Kg m/s2, or a Newton (N).

Re: Weights and measures

Wed, 14 Nov 2012 13:15:01 EDT

BF69 posted :

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

Re: Weights and measures

Wed, 14 Nov 2012 12:08:31 EDT

cowboyro posted :

said by InvalidError:

The difference is that weights, volumes, lengths, etc. are physical measurements that can vary with temperature, humidity, physical wear,

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

said by InvalidError:

Another possibility is your IP address getting spammed by portscans and other activities which AT&T cannot really tell apart from regular traffic in which case the only way to avoid it is to turn off the modem when not in use.

With Uverse, modem off means no TV. Not even being able to watch already recorded shows...

Re: Weights and measures

Wed, 14 Nov 2012 11:42:08 EDT

InvalidError posted :

said by IowaCowboy:

They also inspect gas pumps to make sure that you are getting a true gallon and they inspect scales that are used for trade.

The difference is that weights, volumes, lengths, etc. are physical measurements that can vary with temperature, humidity, physical wear, etc. so these need a common reference preferably tied to some fundamental physical measurements.

Bits on the other hand are a discrete invariant quantity so there is no possible dispute about the measurements of a bit.

What is more dispute-worthy here is the accounting behind the billing: what gets counted, why, where, when and how.

A lot of the billing errors may either be due to AT&T's systems having the wrong port associated with a given account and billing the wrong person. Another possibility is your IP address getting spammed by portscans and other activities which AT&T cannot really tell apart from regular traffic in which case the only way to avoid it is to turn off the modem when not in use. AT&T also cannot really tell packets dropped at your end and even if they could, I doubt there is any reason for AT&T to offer refunds for data mishandled at your end just like the gas station doesn't refund you if you spill gas.

Usage billing is all in the accounting. The likelihood of "measurement" errors from reading byte counters is practically zero.

Re: Weights and measures

Wed, 14 Nov 2012 11:30:35 EDT

en103 posted : I agree. While I'm typically not for 'regulation', I would have to state that if companies that are using meters for profit, those meters should be certified for use by an independent company.

Eg. Household electric meters, gas meters, water meters, grocery store scales, gas station pumps, etc.

If AT&T is going to bill by the byte, then their billing must conform to a standard, and their devices must be certified for accuracy.

I should not be paying for external broadcast packets that do not make it to the LAN side of the modem, or corporate sniffers.

Re: Weights and measures

Wed, 14 Nov 2012 10:43:53 EDT

MaynardKrebs posted :

said by talz13:

said by IowaCowboy:

When you pay for a gallon of gas, it should be a true gallon of gas.

It is always a gallon of gas, but due to temperature fluctuations, it may not be the same mass due to higher densities in cold temperatures, and lower densities in warmer temperatures.

In Canada, the gas is sold volumetric corrected to a temperature of 15C, which is the typical temperature of the gasoline in the underground tanks at the depth they are buried. Since the path of the gasoline in the above-ground portion of the pump is short there is no appreciable need to correct for the ambient atmospheric temperature.

You *might* gain some energy content advantage is you filled up in the winter just after the underground tanks were replenished, if the tanker had traveled 200 miles in -20F weather and chilled the gasoline.

Re: Weights and measures

Wed, 14 Nov 2012 10:37:41 EDT

BF69 posted :

said by talz13:

said by IowaCowboy:

When you pay for a gallon of gas, it should be a true gallon of gas.

It is always a gallon of gas, but due to temperature fluctuations, it may not be the same mass due to higher densities in cold temperatures, and lower densities in warmer temperatures.

Small fluctuations are expected. If someone's data is off 20% that's an issue. Even 5% is an issue.

Re: Weights and measures

Wed, 14 Nov 2012 10:29:27 EDT

travelguy posted :

said by talz13:

It is always a gallon of gas, but due to temperature fluctuations, it may not be the same mass due to higher densities in cold temperatures, and lower densities in warmer temperatures.

Re: Weights and measures

Wed, 14 Nov 2012 09:43:31 EDT

talz13 posted :

said by IowaCowboy:

When you pay for a gallon of gas, it should be a true gallon of gas.

It is always a gallon of gas, but due to temperature fluctuations, it may not be the same mass due to higher densities in cold temperatures, and lower densities in warmer temperatures.

Weights and measures

Wed, 14 Nov 2012 09:18:08 EDT

IowaCowboy posted : If money is involved, then they may be running afoul of various state "weights and measures" laws.

Here in Massachusetts (although we are Verizon turf), the weights and measures laws are somewhat strict such as a store can get a $100 fine if the price on the shelf and the price on the scanner does not match. They also inspect gas pumps to make sure that you are getting a true gallon and they inspect scales that are used for trade.

Maybe some class action lawyer could find a way to convince a judge to apply the various weights and measures laws since they do charge for overages.

When you pay for a gallon of gas, it should be a true gallon of gas. And in Mass, the price on the pump and the price on the signs have to match or you are entitled to the lower price.