Wikidata:Property proposal/Rotational speed

rotational speed[edit]

Originally proposed at Wikidata:Property proposal/Natural science

Not done

Description	Rotational speed (also known as speed of revolution or rate of rotation), of an object rotating around an axis is the number of turns of the object divided by time, specified as revolutions per minute (rpm), cycles per second (cps), radians per second (rad/s), etc.
Represents	rotational speed (Q1256787)
Data type	instance of (P31)-invalid datatype (not in Module:i18n/datatype)
Template parameter	Common symbols ω (omega), SI unit rad/s, Derivations from other quantities ω = v / r, Dimension T^-1)
Allowed units	revolutions per minute (Q206037), hertz (Q39369), radian per second (Q1063756)
Example 1	Caterpillar 3516C (Q115044805) (an engine (Q44167)) → 1600 rpm (revolutions per minute (Q206037))
Example 2	PSR J1748-2446ad (Q119583) (a neutron star (Q4202)) → 716 cps (hertz (Q39369))
Example 3	Earth (Q2) → (7.292 115 0 ± 0.000 000 1) x 10⁻⁵ rad/s (radian per second (Q1063756))
Example 4	Guardian-class patrol boat (Q48815436) → powered by (P516) → Caterpillar 3516C (Q115044805) → rotational speed (Q1256787) → 1600 rpm (revolutions per minute (Q206037))
Planned use	Adding rotational speed (in rpm) to "powered by"-statement on ship class item. (powered by (P516) → engine (Q44167) → rotational speed (Q1256787)) → 1600 revolutions per minute (Q206037)
Wikidata project	WikiProject Physics (Q8487193), WikiProject Astronomy (Q8493596), WikiProject Aviation (Q53054), WikiProject Motorsport (Q10803551), WikiProject Ships (Q10782171)

Motivation[edit]

Adding rpm to qualifiers for "powered by"-statement on ship class item. Would it be appropriate to also approve properties for rpm, cps and rad/s alongside this? Or are units not properties? (I'm new to WikiData.) BucketOfSquirrels (talk) 19:44, 22 October 2022 (UTC)[reply]

Discussion[edit]

@BucketOfSquirrels: Units are items - revolutions per minute (Q206037) and radian per second (Q1063756) for instance. You can list them in the "allowed units" field of the proposal form. Can you fix up the examples so they refer to actual existing wikidata items in the way that you envision this actually being used (you do plan to use it as a qualifier?) ArthurPSmith (talk) 15:55, 25 October 2022 (UTC)[reply]
Added the changes you suggested. As far as I understand it; when a vessel has a (powered by (P516) → engine (Q44167)-statement then the rotational speed (Q1256787)) → 1600 revolutions per minute (Q206037)-statement for that engine is a qualifier. I could easily be wrong. I'm fairly new to these specific definitions. BucketOfSquirrels (talk) 18:47, 25 October 2022 (UTC)[reply]
Comment I think this property should be named "maximal rotational speed" because that is how it is going to be used in most cases. Relatively few object have constant rotational speed (like Earth (Q2)) while this property is probably going to be used mostly for engines and similar. /ℇsquilo 17:29, 25 October 2022 (UTC)[reply]
Should there be two properties for this? (Constant and maximal.) Could there be a must-include qualifier that defaults to maximal? Presumably, items should only have one. BucketOfSquirrels (talk) 19:00, 25 October 2022 (UTC)[reply]

If there should be two separate properties for this; would there need to be a second proposal? Could a property creator or administrator create multiple properties from a single proposal, if there was consensus on how to implement them? BucketOfSquirrels (talk) 20:42, 3 November 2022 (UTC)[reply]
You can add a second property to the same proposal page, but I don't think that creating two "rotational speed" properties is the right way to go in this case. — The Erinaceous One 🦔 22:58, 6 November 2022 (UTC)[reply]
~~Support~~ [Edit: retracted support. See comment below.] for astrononmical bodies that have a (relatively) constant rotation speed. The modeling for, say, engines that have variable rotation speeds needs more work. — The Erinaceous One 🦔 00:47, 27 October 2022 (UTC)[reply]
Oppose in current form because the property is imprecise about whether it's a claim about maximum or constant speed.

Given that different engines have different rotational speeds the current example for them is invalid. The same goes for neutron star where I would be very surprised if all neutron stars have a rotational speed of 716 cps. If you want to use it for ships please bring concrete examples of how you want it to be used. ChristianKl ❪✉❫ 19:51, 2 November 2022 (UTC)[reply]
Right, it wouldn't make sense to have neutron star (Q4202)rotational speed716 Hz, as in example 2, but it would be useful to have PSR J0659+1414 (Q28456392)rotational speed2.597 Hz (PSR J0659+1414 (Q28456392) is a neutron star). It would be pretty cool to be able to plot the angular velocity of planets, stars, etc. — The Erinaceous One 🦔 03:49, 3 November 2022 (UTC)[reply]

I edited the examples to be more specific. I initially left them generic as they can be applied to a variety of engines and celestial objects. Do you think this should be two properties or is it possible to add a must-include qualifier? BucketOfSquirrels (talk) 20:42, 3 November 2022 (UTC)[reply]
~~What qualifier were you thinking for the "must include qualifier"?~~ [Edit: I see your comment above, now, that clarifies what you meant.] For engines, I think we would need a "has quality -> maximum value" qualifier for the statement to be meaningful. — The Erinaceous One 🦔 22:57, 6 November 2022 (UTC)[reply]
If this proposed property is to be used as a qualifier, though, there can’t be a (meta-)qualifier “has quality: maximum value” on the qualifier ‘rotational speed’ (Pxxx), right? So if we are to allow its use as a qualifier, it would have to be specific enough in itself. In the engine–boat scenario, that could be something like “nominal rotational speed” (German:
Nenndrehzahl
, etc.); and in that case, we should leave stellar rotational velocity (P4296) as is … ―BlaueBlüte (talk) 12:49, 30 January 2023 (UTC)[reply]
Comment I retract my previous support because there already exists the property stellar rotational velocity (P4296). It would be better to modify that property to apply to all astronomical bodies instead of creating a new property. Perhaps we want to make a new property that is specifically for maximum rotational velocity of engines? – The preceding unsigned comment was added by The-erinaceous-one (talk • contribs).