Under the post about dividing the day into 10/100/100 parts, many people said "second is the metric unit of time" and I agree, but what if we would made decimal time using seconds?

The idea is: keep the old second, but add SI prefixes

We want equivalents of minute and hour so I suggest:

Hectosecond (hs)

Kilosecond (ks)

Megasecond is too big (~2 weeks) and metric wiki fandom (yes it exists) suggested myriasecond as an new hour, but

1. It divides day into 9 parts and with 10 parts, some people said that they need smaller denominations

2. Myria- isn't a SI prefix

So hectosecond and kilosecond are still my types

There are pros:

1. It's decimal, and metric fans like decimal units

2. Hour wouldn't be a problem ever again:

km/h? Now its km/ks which is exacly m/s

kWh? Now it's kW•ks or exacly 1 MJ etc.

I still suggest using unit "day" until the moment that humanity will colonize the solar system, when "day" would mean nothing for people from Mars, but for today it's pretty useful

Of course there are cons:

1. Day splited like that would have 86,4 ks, with is not terrible number, but it's still not round, so it's kinda problematic I guess

2. 24/60/60 survived for thousands of years

3. 10 and 100 doesn't have as many divisors as 60 and 24

So I'm not sure is it a good idea or not

So what do you guys think? Should we use second as a base and then add prefixes, or keep 24/60/60?

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Base units

Length — meter (m)

Time — second (s)

Mass — kilogram (kg)

Temperature — kelvin (K)

Electric current — ampere (A)

Luminous intensity — candela (cd)

Amount of substance — mole (mol)

Plane angle — radian (rad)

Solid angle — steradian (sr)

Mechanics and kinematics

Force — newton (N)

N = kg · m / s²

N = J / m

Mass density — arch (Ar)

Ar = kg / m³

Ar = Vn / Bn

Momentum — huygens (Hy)

Hy = kg · m / s

Hy = N · s

Pressure — pascal (Pa)

Pa = N / m²

Pa = kg / (m · s²)

Pa = J / m³

Dynamic viscosity — poiseuille (Pl)

Pl = Pa · s

Pl = kg / (m · s)

Surface tension — laplace (Lp)

Lp = N / m

Lp = J / m²

Gravitational potential — gal (G)

G = J / kg

G = (kg · m² / s²) / kg

G = m² / s²

Thermodynamics

Energy / Work / Heat / Enthalpy — joule (J)

J = N · m

J = (kg · m / s²) · m

J = kg · m² / s²

J = W · s

Heat capacity — clausius (Cl)

Cl = J / K

Cl = kg · m² / (s² · K)

Specific heat capacity — meyer (My)

My = J / (kg · K)

My = m² / (s² · K)

Power — watt (W)

W = J / s

W = kg · m² / s³

W = V · A

Action — planck (Pk)

Pk = J · s

Pk = (kg · m² / s²) · s

Pk = kg · m² / s

Entropy — boltz (Bz)

Bz = J / K

Bz = W · s / K

Thermal conductivity — fourier (Fo)

Fo = W / (m · K)

Fo = kg · m / (s³ · K)

Fluid dynamics

Mass flow rate — venturi (Vn)

Vn = kg / s

Vn = Ar · Bn

Volumetric flow rate — bern (Bn)

Bn = m³ / s

Bn = m² · m / s

Waves

Frequency — hertz (Hz)

Hz = s⁻¹

Hz = 1 / s

Angular frequency — poincare (Pn)

Pn = rad / s

Pn = s⁻¹

Electromagnetism

Electric potential — volt (V)

V = J / C

V = W / A

V = kg · m² / (A · s³)

Electric charge — coulomb (C)

C = A · s

C = F · V

Volume charge density — franklin (Fr)

Fr = C / m³

Fr = A · s / m³

Surface electric current density — giorgi (Gi)

Gi = A / m²

Gi = C / (s · m²)

Resistance — ohm (Ω)

Ω = V / A

Ω = kg · m² / (A² · s³)

Ω = 1 / S

Capacitance — farad (F)

F = C / V

F = A² · s⁴ / (kg · m²)

F = S · s

Inductance — henry (H)

H = Wb / A

H = V · s / A

H = kg · m² / (A² · s²)

Conductance — siemens (S)

S = A / V

S = 1 / Ω

Electric displacement — roentgen (Ro)

Ro = C / m²

Ro = Cv · E

Electric field flux — gauss (Gs)

Gs = E · m²

Gs = V · m

Magnetic field flux — weber (Wb)

Wb = V · s

Wb = T · m²

Wb = kg · m² / (A · s²)

Electric permittivity — cav (Cv)

Cv = F / m

Cv = A² · s⁴ / (kg · m³)

Magnetic permeability — max (Mx)

Mx = H / m

Mx = kg · m / (A² · s²)

Electric field strength — edison (E)

E = V / m

E = N / C

E = kg · m / (A · s³)

Magnetic field intensity — tesla (T)

T = Wb / m²

T = N / (A · m)

T = kg / (A · s²)

Optics and radiation

Luminous flux — lumen (lm)

lm = cd · sr

Illuminance — lux (lx)

lx = lm / m²

lx = cd · sr / m²

Vergence — descartes (Dc)

Dc = m⁻¹

Dc = rad / m

Radiance — stefan (St)

St = W / (m² · sr)

St = kg / (s³ · sr)

Irradiance / EM flux density — poynting (Py)

Py = W / m²

Py = kg / s³

Volume power density — opp (O)

O = W / m³

O = kg / (m · s³)

Acoustics

Sound power — bel (B)

Sound impedance — rayleigh (Ry)

Ry = Pa / (m / s)

Ry = kg / (m² · s)

Nuclear and chemistry

Absorbed dose — gray (Gy)

Gy = J / kg

Gy = m² / s²

Equivalent dose — sievert (Sv)

Sv = J / kg

Sv = m² / s²

Radioactive activity — becquerel (Bq)

Bq = s⁻¹

Bq = 1 / s

Catalytic activity — katal (kat)

kat = mol / s

kat = mol · Hz

I've been trying to figure out how to create 1 centimeter in a medieval world using medieval technology, but I haven't found a single method that actually works within the medieval working environment.

In SI system (and units allowed to use) we've got 4 units of power:

Watt

Volt-ampere

Var

Kilowatt-hour per 1.000 hours

They have exacly the same value [kg m^(2) s^(-3)] but they are use for diffrent powers

Watt — active power

Volt-ampere — Apparent power

Var — reactive power (it's name is a shortcut of "volt-ampere reactive")

(Kilowatt-hour per 1.000 hours is used in Europe for electronic/electric devices)

And it's crazy, we could just use watt for everything, but we've got 4 units.

We can at least Justify first 3 of them, insted of writing which power are we talking about, we can use diffrent unit and every engineer knows what power are you talking about, but it's not exacly true, because all of them [diffrent powers] have diffrent symbols.

kWh/1.000 h is crazy, why not simple watt, here I don't even know how to justify it

What do you think guys? Shoud we use all of them, keep only few or use one unit of power (watt)?