Editing Mass

'''Mass''' is a fundamental concept in [[physics]], representing the amount of [[matter]] in an object. It is a scalar quantity, meaning it only has magnitude and no direction. Mass is typically measured in [[kilogram]]s (kg) in the [[International System of Units]] (SI), but can also be measured in [[gram]]s (g), [[pound]]s (lb), or other units.

== Definition ==

In physics, mass is defined as the measure of an object's resistance to [[acceleration]]. This is known as [[inertia]]. The more mass an object has, the more force is required to change its speed or direction. This relationship is described by [[Newton's second law of motion]], which states that the force applied to an object is equal to the mass of the object multiplied by its acceleration (F = ma).

== Measurement ==

Mass is measured using a [[balance scale]], which compares the mass of the object being measured to the mass of a set of known weights. This is different from measuring weight, which is the force exerted by gravity on an object. Because the force of gravity can vary depending on location, an object's weight can change, but its mass remains constant.

== Types of Mass ==

There are several types of mass in physics, including [[rest mass]], [[inertial mass]], and [[gravitational mass]]. Rest mass is the mass of an object as measured when it is at rest relative to an observer. Inertial mass is the mass of an object as determined by its resistance to acceleration. Gravitational mass is the mass of an object as determined by the force of gravity it exerts on other objects.

== Mass in Relativity ==

In [[Einstein's theory of relativity]], mass is not always conserved. Instead, mass and energy are interchangeable, as described by the famous equation E=mc^2. This means that an object can gain or lose mass by gaining or losing energy.

== See Also ==

* [[Weight]]
* [[Matter]]
* [[Force]]
* [[Acceleration]]
* [[Inertia]]
* [[Newton's laws of motion]]
* [[Relativity]]

[[Category:Physics]]
[[Category:Fundamental physics concepts]]

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<gallery>
File:Poids_fonte_2_kg_03_(cropped).jpg|Poids fonte 2 kg
File:SI_base_unit.svg|SI base unit
File:Mass_versus_weight_in_earth_and_mars.svg|Mass versus weight in earth and mars
File:Apollo_15_feather_and_hammer_drop.ogv|Apollo 15 feather and hammer drop
File:El_pesado_del_corazón_en_el_Papiro_de_Hunefer.jpg|El pesado del corazón en el Papiro de Hunefer
File:Galileo.arp.300pix.jpg|Galileo
File:Falling_ball.jpg|Falling ball
File:GodfreyKneller-IsaacNewton-1689.jpg|Isaac Newton
File:Newton_Cannon.svg|Newton Cannon
File:Universal_gravitational_mass.jpg|Universal gravitational mass
File:Cavendish_Experiment.png|Cavendish Experiment
File:Massmeter.jpg|Massmeter
</gallery>