**Weight. **In __Physics__ terms , weight is the __force__ of a __body__ acting on a support point, caused by the acceleration of __gravity__ , when it acts on the body’s mass. Weight is itself a __vector quantity__ , so it is characterized by its __magnitude__ and direction, applied at the body’s center of gravity and directed roughly towards the center of the __Earth__ .

Summary

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- 1 Weight and mass
- 2 weight units
- 1 International System of Units
- 2 Technical Unit System
- 3 Other Systems

- 3 Weight calculation
- 4 Sources

Weight and mass

The mass of a body is a characteristic property of it, which is related to the number and class of the particles that make it up. It is measured in kilograms (kg) and also in grams, tons, pounds, ounces, etc.

The weight of a body is the force with which it is attracted to the Earth and depends on its mass. One body of mass twice as much, it also weighs twice as much. It is measured in __Newtons__ (N) and also in kg-force, dynes, pound-force, ounce-force, etc.

The kg is therefore a unit of __mass__ , not weight. However, many devices used to measure weights (scales, for example), have their scales graduated in kg instead of kg-force. This is usually not a problem, since 1 kg-force is the weight on the Earth’s surface of an object of 1 kg mass.

Therefore, a person weighing 60 kg weighs 60 kg-Force on the Earth’s surface. However, the same person on the __Moon__ would weigh only 10 kg-force, although his mass would still be 60 kg. (The weight of an object on the Moon represents the force with which it draws it)

Weight units

International System of Units

The physical quantities are expressed in units of __the international system of units__ (SI). Thus, the weight is expressed in SI force units, that is, in newtons (N): 1 N = 1 kg. 1 m / s²

Technical System of Units

In the __Technical System of Units__ , weight is measured in __kilogram-__ force (kgf) or __kilopond__ (kp), defined as the force exerted on a kilogram of mass by the acceleration in free fall (g = 9.80665 m / s²) [3] .

So: 1kp = 9.80665 N = 9.80665 kg.m / s²

Other Systems

Weight is also often indicated in other systems, such as dyna, pound-force, ounce-force, and so on.

Weight calculation

The calculation of the weight of a body from its mass can be expressed using the second __law of dynamics__ :

Where the value of is the __acceleration__ of __gravity__ (see) in the place where the body is. In the first approximation, if we consider the Earth as a homogeneous sphere, it can be expressed with the following formula: