What Is kilogram-force square second/meter?
The kilogram force square second per meter is a special way to measure mass. It connects three ideas in physics force, time, and distance. Today it is mostly a historical or teaching unit, not something people use in everyday life.
Definition
The kilogram force square second per meter shows how much mass will change its motion when a certain force acts on it over time and distance.
In simple words, it is the amount of mass that is pushed with a force of one kilogram force and speeds up by one meter per second every second.
In physics form, the unit looks like this:
- kilogram force second squared per meter
- written as kgf s²/m
By the laws of physics, this unit turns out to be a unit of mass. It is equal to about 9.80665 kilograms.
History / Origin
The kilogram force second squared per meter comes from older ways of measuring called gravitational systems. In those systems, people liked to use kilogram force instead of the newton to measure force.
Scientists and engineers wanted a matching mass unit for kilogram force, similar to how the slug matches the pound force in the English system. So they built a mass unit from:
- kilogram force for force
- second for time
- meter for length
This combination, kilogram force times second squared divided by meter, became a mass unit. In some books it is also called the hyl or metric slug.
Over time, the modern SI system, which uses newtons for force and kilograms for mass, replaced this older style. Because of this, kilogram force second squared per meter is now mainly a historical or educational unit.
Symbol & Abbreviation
The common symbols and short forms are:
- Full name kilogram force square second per meter
- Main symbol kgf s²/m
- Sometimes written as kgf·s²/m or kgf s^2/m in plain text
- Traditional name hyl or metric slug
All of these refer to the same physical unit of mass.
Current Use Around the World
Today, this unit is rarely used in real work. Most countries and industries use the SI system with:
- kilogram (kg) for mass
- newton (N) for force
The kilogram force second squared per meter may still appear in:
- older engineering or physics textbooks
- historical papers and tables
- special discussions about non SI or gravitational unit systems
Modern standards and science guides do not recommend using kilogram force or this derived unit in new work. They are mainly kept for understanding and converting old data.
Example Conversions
Here are some useful conversion values. The standard value of gravity used is 9.80665 meters per second squared.
To kilograms
- 1 kgf s²/m ≈ 9.80665 kg
- 2 kgf s²/m ≈ 19.6133 kg
- 5 kgf s²/m ≈ 49.0333 kg
- 10 kgf s²/m ≈ 98.0665 kg
From kilograms
- 1 kg ≈ 0.10197 kgf s²/m
- 10 kg ≈ 1.0197 kgf s²/m
- 50 kg ≈ 5.0985 kgf s²/m
To grams
- 1 kgf s²/m ≈ 9 806.65 g
- 0.1 kgf s²/m ≈ 980.665 g
To slugs (English mass unit)
1 slug ≈ 14.5939 kg.
- 1 kgf s²/m ≈ 9.80665 kg ≈ 0.6720 slug
- 5 kgf s²/m ≈ 49.0333 kg ≈ 3.3598 slug
These numbers are rounded, so small differences may appear if you use more decimal places.
Related Units
The kilogram force second squared per meter is closely linked to these units:
- Kilogram (kg) main SI unit of mass
- Newton (N) main SI unit of force, 1 N = 1 kg m/s²
- Kilogram force (kgf) force equal to the weight of 1 kg at standard gravity, about 9.80665 N
- Hyl or metric slug another name for the same mass unit as kgf s²/m
- Slug mass unit in the English system that matches pound force
FAQs
Is kilogram force second squared per meter a unit of mass or force?
It is a unit of mass. Even though it contains kilogram force in its name, the way it is built makes its physical dimension equal to mass.
Why does this unit include kilogram force instead of newton?
It comes from older gravitational unit systems, where engineers liked to use kilogram force as the main force unit. The unit kgf s²/m was then created to match that system, just as the slug was made to match the pound force.
Is kilogram force second squared per meter part of the SI system?
No. The SI system uses kilograms for mass and newtons for force. Kilogram force and units made from it, like kgf s²/m, are considered non SI units.
Where might I still see this unit used?
You might see it in old engineering books, historical physics tables, or when people talk about gravitational unit systems. It is very rare in modern design or research work.
What is the simple conversion between kgf s²/m and kilograms?
One kilogram force second squared per meter equals about 9.80665 kilograms. To go the other way, one kilogram is about 0.10197 kilogram force second squared per meter.
Is it better to use kilograms instead of this unit today?
Yes. For all new work, it is best to use kilograms for mass and newtons for force. This follows the SI system and avoids confusion with older units.
