Metre–tonne–second system of units

The metre–tonne–second system of units was invented in France where it became the legal system between 1919 and 1961. It was adopted by the Soviet Union in 1933 and abolished there in 1955. It was a coherent metric system of units, much as SI and the centimetre–gram–second system, but with larger units for industrial use, whereas the CGS system was regarded as only really suitable for laboratory use.

Units

The base units of the MTS system are:

Length: metre
Mass: tonne,
: 1 t = 10³ kg = 1 Mg
Time: second

Some common derived units:

Volume: cubic metre or stere
: 1 m³ ≡ 1 st
Force: sthène,
: 1 sn = 1 t⋅m/s² = 10³ N = 1 kN
Energy: sthène-metre = kilojoule,
: 1 sn⋅m = 1 t⋅m²/s² = 10³ J = 1 kJ
Power: sthène-metre per second = kilowatt,
: 1 sn⋅m/s = 1 t⋅m²/s³ = 10³ W = 1 kW
Pressure: pièze,
: 1 pz = 1 t/m⋅s² = 10³ Pa = 1 kPa = 1 cbar