Physics for Everyone: Guide to Basic Physics #2 The Technical System

Also called a system of engineers or a gravitational system, it is a metric, not absolute, inhomogeneous and incomplete system that takes the length, strength and time intervals as the fundamental magnitudes and uses as a unit of measure the meter, the kilogram- strength (or kilogram-weight) and the second. The kilogram-force (kgf) is defined as the force applied to a body mass of 1 Kg, which produces an acceleration equal to that of sample gravity, fixed at 9.80665 m / s ^ 2.

it's easy to get that:
1Kgf= 9.80665 N

In this system, therefore, the mass unit is a derived unit; it is indicated by um and it is worth 9.80665 kg.
The unit of work and energy is the kilogrammeter (kgf m, more rarely kgm), defined as 1 Kgf 1 m and equal to 9.80665 J.
The power unit is kgf m / s, of which a multiple called horsepower (CV) is used, defined exactly as 75 kgf m / s = 735,499 W.
The pressure unit is Kgf / m ^ 2, corresponding to the millimeter of water (mm H2O).

To obtain the conversion factors between the technical units and the corresponding units of the other systems, it is enough to remember that 1 Kgf = 9.80665 N, 1um = 9.80665 kg, which are both derived from the second law of dynamics. if you remember that while the 1 N force accelerates the mass of 1kg acceleration of 1m / s ^ 2, the force of 1 kgf gives it an acceleration of 1 m / s ^ 2, and the force of 1 kgf gives it instead an acceleration of 9.80665 m / s ^ 2.

See you soon with the International System of Units and its history.