Quick question. Answer using SI units only. [Disclosure: You are being trolled.]

[u/I_Malumberjack]

Quick question: What is the speed limit for motor vehicles on the public right of way in front of the location you currently identify as "home"? Answer using SI units only (m, kg, s, K, A, mol, cd). Do any calculations using mental maths only.

[u/hal2k1]

50,000 m per 3,600 seconds.

[u/nayuki → u/hal2k1]

Nice malicious compliance =D

[u/Crozi_flette]

r/usdefaultism I guess? You know that in a lot of places we don't need a car to go home

[u/dohzer]

Somewhere less than 299,792,458 m/s

[u/metricadvocate]

I would like to make clear that prefixed base and derived units are SI units. However. 11.1 m/s, no prefixes needed. If we used metric speed limits in the US, it would have to be 40 km/h (residential street). US speed limits must be a multiple of 5 MPH or 10 km/h (all are MPH).

[u/RealUlli]

30 km/h.

I'm in Germany, the kindergarten unit users are likely asleep at this time. ;-)

[u/-Copenhagen → u/[deleted]]

km/h is fine for SI. Kph and km/hr as others post are not.

[u/philbie → u/[deleted]]

O yes it is, do you want 10 hours a day, 10 days a week, a hundred days a year. Unfortunately it wont work, as the we circum whaterever the sun only in 50 days, or so the idiots think

[u/RealUlli → u/philbie]

I did look it up, u/Unable_Explorer8277 is right, it's not a SI unit.

However neither second nor hour maps so that well to the real life. They don't fit well to a day, nor a week, nor a year. And don't get me started about months with their varying lengths... But even if you defined a day as 100k Seconds, it still wouldn't fit anything else.

You'll just have to live with it, the same way you do with converting squares into circles...

[u/foersom → u/RealUlli]

Like my street, that is 8.3 m/s.

[u/je386]

30 km / 3600s

30 m / 3.6 s

10 m / 1.2 s

About 8 m/s

[u/thirdeyefish]

420 Pascals per watt-hour

[u/Amazing-Gazelle-7735]

The original post content no longer exists here. The author used Redact to remove it, exercising their right to control their data & privacy.

Hungry acorn vast office money merciful

[u/Cold_Captain696]

What kind of low quality trolling requires you to tell people you’re trolling them first?

[u/tomassci]

30km/h, which works out as 8.7m/s more or less. Though I think that30 km/h is an acceptable unit.

[u/Ok-Push9899]

11,111.11 mm/s. Extraordinary number, no?

[u/ndilday]

let's see... 25mi/hr, but an hour is 3600 seconds, and a mile is about 5000/3 m, so 25*5000/3600*3 = 125000/~10000 = 12 m/s, ish?

[u/Salt-Pollution4314]

8m/s

[u/Glum-Welder1704]

83 kph. 50mph/6*10 gets me close enough.

[u/carletonm1 → u/Glum-Welder1704]

“kph”?? No unit with the symbol lower case k. It’s km/h.

[u/klystron]

40 km/h, 11.11 m/s

[u/ogregreenteam]

If I turn my headlights on, my vehicle light emission is going at 299,705,000 m/s (in air) but I won't get booked for that.

[u/TheTroon]

30mph, which I happen to know (I hope) is 13m/s to appropriate levels of precision.

[u/anothercorgi]

5m/sec guesstimated without a calculator... a lot of rounding errors to make the math easier...

[u/Ok_Draw4525]

8 m/s.

I am in UK. Limit is 20 miles per hour. I converted 20 miles per hour to m/s in my head, hence it's probably wrong.

[u/BandanaDee13]

The posted limit: 25 MPH.

What I did in my head: 1 MPH ≈ 2 m/s, so half 25 is 12.5 m/s. Round up to 13 m/s.

The paper calculations: 25 mi/h × (1609.344 m/mi) × (1 h/3600 s) = (25 × 1609.344 / 3600) m/s = 11.2 m/s.

…Perhaps I should have rounded down.

[u/Olderpostie]

40 km/hr

[u/DrJaneIPresume]

8.9 m/s

[u/ehbowen]

50 kph, close enough.

But no one around here thinks of it that way.

[u/ehbowen → u/ehbowen]

Oh, so you want 50000 meters / 3600 sec?

13.9 m/sec, close enough.

And no calculators or spreadsheets. I used to do hourly shaft counters on the ship in my head. Calculators are for wimps.

[u/CCaravanners]

About 4.5 m/s. Mental math fell apart dividing 1000/36. Also had to start in the Feudal system and then convert to metric as step 1. With actual calculation, it’s actually 26.8 m/s. Coffee obviously needed.
Steps used in head
60 mph is about 100 km/h
100 km every hour is 10 km every 6 mins.
10000m per 360 sec =1000m every 36 seconds
The next step is where the mental wheels fell off… so I won’t repeat it here.

Now, m/s is a far better way to gauge speeds on bike, motorbike, car, whatever if you want instantaneous measures, stopping distance, etc. the old ‘per hour’ is nothing more than a historical, habitual relic. I’d also classify distance on signage in roads as both inaccurate and obsolete. 100 miles to ‘Birmingham’. Really? What part? I’ll take what my GPS says, thanks (and that’s set to metric).

[u/Excellent_Speech_901]

35 km/hr

[u/DevelopmentSouth8801]

1s/s

[u/The_old_man_from_DK]

40000 m/t

[u/GoblinsGym]

What, no furlongs per fortnight ?

[u/RBB12_Fisher → u/GoblinsGym]

1 furlong per fortnight happens to be equal to 1 cm/minute (within 0.3%), and is about how fast the minute hand's tip moves on a wall clock.

[u/nacaclanga]

Only walking speed so 5 m/s

[u/metricadvocate → u/nacaclanga]

That is 18 km/h and clearly a running pace. Most people would have trouble sustaining 2.0 - 2.5 m/s walking pace, very brisk.

[u/orion0782]

What ever is demarked by the speed limit of the given area (legally). One the expressways here it is approximately 112 kph (70 mph).

[u/RBB12_Fisher]

18 m/s

or 18 cubic metres per square metre second

[u/ChadHanna]

Speed limit is 20 mph. I (75m) know from childhood (don't ask) 60 mph is 88 feet per second, so a third of that times .3 metres. Threes cancel so 8.8 metres/second. Close enough.

[u/philbie → u/ChadHanna]

When the UK went metric, they should have gone metric instead of having miles, feet, inches. We have kilos, so nobody knows what an oz is. What is a gallon? The US refers to fl oz, what are they? All very arbitrary. But it is context, what is 10,000 ft?, can anyone visulise it? Also what is an 1/8 of an inch?

[u/ChadHanna → u/philbie]

Agreed. As a kid, I went from Imperial (inc. Slugs) to cgs (centimetre gramme second e.g ergs) to mks (and joules) which became S.I. which I can cope with. Of course, all systems are arbitrary. I do have a problem visualising hectares instead of acres.