My Uconeer units converter does not have that idiosyncrasy.

Hi. I'm quite sure this three guys think that rpm in SMath is well defined.







RPM_IN_PRACTICE.sm (563kb) downloaded 11 time(s).

Alvaro.

Claiming SI units are wrong would be ridiculous.
This is how recent SI units are printed.
If they change it later in future, than I will defend what they write at that time.
If you want to achieve 0.0167 Hz in smath, use derived unit radpm.

Regards

When you realize one revolution is not considered as 1, but as 2π in SI, then you will be convinced.
Otherwise, I can do nothing. There lays all standardization documents. Read them, carefully, and be ready to your world destructed in shambles.

No need to argue, let's agree to disagree. But SMath's units shall respect to SI units, beware of that.

Nope. Your error is here:



I don't specify units, I (and those three guys, if you don't know them, it could be a good read for introduce some basics) specify dimensions, not units. Radians are not unitless, they are an unit, are dimensionless, which isn't the same. For instance, masons, architects and civil engineers often measure the slopes of their angles in buildings in cm / m, quantities that are dimensionless but certainly have units.

Following your line of reasoning, you should tell Norton to correct his book, as his torque values (lbf-in) are badly wrong because he forgot to include radians. Or you don't measeure torques in energy units? Because I do. And Norton too.



Alvaro.

Edited by user 30 November 2021 08:51:59(UTC)  | Reason: Not specified

I concede that I used the wrong word (unitless), but the difference is semantic only. The intended meaning is not changed by using "dimensionless" instead.


As overlord included in a recent response, SMath interprets rads per minute in the same way that most people interpret revolutions per minute, and vice-versa. Which is wholly confusing:

60 rpm = 2π Hz
60 radpm = 1 Hz

versus:

60 rad/min = 60/(2π) revolutions/min = 1/(2π) cycle/s = 1/(2π) Hz


And it makes sense that the "frequency" in torque is angular frequency, because torque is the rotational equivalent to a moment (force x distance) and work (force x distance). Radians provide a 1:1 relationship between rotational work and linear work.

But Hz is a unit of (inverse) time. As far as I can tell, the SI standard ALLOWS for rad = (1) when used with Hz, but it doesn't define it as such. (In fact, it seems horribly obstinate about such a definition.)

I would argue that the "long-established practice ... of rad = 1" is equally as common as the understanding of Hz = 1 cycle/s (where, by SI definition, "cycle" is also dimensionless and thus cycle = 1).

It's clear from what I've read that both "1 rad/s = 1 Hz" and "1 cycle/s = 1 Hz" are acceptable by SI standards, and both have their uses, but when you says "This value is ___ Hz" to 99% of the scientific community, they'll assume you mean "This value is ___ cycles per second" (unless the context provides clues otherwise, such as when using ω or when speaking specifically about angular frequency, such as with torque).

So, I would argue that since both are "accepted" and that 1 Hz = 1 cycle/s is the definition MUCH more widely assumed and understood when speaking about frequency, that SMath should treat Hz as cycles per second, along with rpm as cycles per minute, and use rad/s for radians per second and radpm as radians per minute. At the very least, such a change would be more user-friendly and align with the behaviour that the astounding majority of users would expect.

What I have written before that statement is;


I didn't know "scriptures" can be changed.
What kind of religious belief you are in?
I see your ad hominem and withdraw my hand.

Your logic about standards is crippled.
This is science, of course I shall obey its standards and rules.
Until a better rule in it is found and replaced the old one.
Maybe I find the new rule maybe another. (I know I won't)
But it has to be written in related standard.

And the page you have shared is just an article, a paper.
Anyone can write a paper about anything, even with bizarre arguments.
I am not saying all articles has nonsense information. (yours has)
But they should not to be taken as standard's replacements.

Edited by user 30 November 2021 09:47:56(UTC)  | Reason: Not specified

It's a metaphor, not a personal attack...



"Immature" may be more accurate here, but the difference is semantically insignificant, given our mutual lack of acquaintance with one another.



This is technical writing (an important compliment to science). Science is required to develop the content, and may be involved in some of the decisions, certainly. But on the whole, standards are about communication - and with communication, clarity is king.



I wasn't implying that the paper overturns the standard (that would be silly). The paper was simply referenced because it highlights the type of ambiguities that have been the source of my frustration and the core of this debate.

Nope, you are wrong.

This is the definition I gathered from Oxford University Press:
Science encompasses the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.
Technology is the application of scientific knowledge for practical purposes.

Defining units and standardizing them is science.
Science establish a base for further use with defining units.
They are even called scientific units, not technical units.

Using scientific knowledge for calculations is technology.
And you calculate technology with technical writings.

Edited by user 30 November 2021 13:23:40(UTC)  | Reason: Not specified

There is no term as Engineering Units in SI. That is an imperial units or derivations term.
Which is used only by 3 countries in whole world; USA, England and Myanmar.
I guess Canadians are having problems too due to their late acknowledge of metric system.