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In [[physics]], '''mass''' (from Ancient [[Greek]] μᾶζα) commonly refers to any of three properties of [[matter]], which have been shown [[experiment]]ally to be equivalent: ''inertial mass'', ''active gravitational mass'' and ''passive gravitational mass''. In everyday usage, mass is often taken to mean [[weight]], but in [[scientific]] use, they refer to different properties.

In [[physics]], '''mass''' (from Ancient [[Greek]] μᾶζα) commonly refers to any of three properties of [[matter]], which have been shown [[experiment]]ally to be equivalent: ''inertial mass'', ''active gravitational mass'' and ''passive gravitational mass''. In everyday usage, mass is often taken to mean [[weight]], but in [[scientific]] use, they refer to different properties.

The inertial mass of an object determines its acceleration in the [[presence]] of an applied [[force]]. According to [http://en.wikipedia.org/wiki/Isaac_Newton Isaac Newton]'s [http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton.27s_second_law second law of motion], if a [[body]] of mass m is subjected to a [[force]] F, its acceleration a is given by F/m.

The inertial mass of an object determines its acceleration in the [[presence]] of an applied [[force]]. According to [https://en.wikipedia.org/wiki/Isaac_Newton Isaac Newton]'s [https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton.27s_second_law second law of motion], if a [[body]] of mass m is subjected to a [[force]] F, its acceleration a is given by F/m.

A body's mass also determines the [[degree]] to which it generates or is affected by a [[Gravity|gravitational field]]. If a first body of mass m1 is placed at a distance r from a second body of mass m2, the first body [[experiences]] an attractive force F given by

A body's mass also determines the [[degree]] to which it generates or is affected by a [[Gravity|gravitational field]]. If a first body of mass m1 is placed at a distance r from a second body of mass m2, the first body [[experiences]] an attractive force F given by

[[File:Mass1.jpg‎]] ,

[[File:Mass1.jpg‎]] ,

where G is the [[universal]] [http://en.wikipedia.org/wiki/Gravitational_constant constant of gravitation], equal to 6.67×10−11 kg−1 m3 s−2. This is sometimes referred to as gravitational mass (when a distinction is [[necessary]], M is used to denote the active gravitational mass and m the passive gravitational mass). Repeated [[experiments]] since the [http://en.wikipedia.org/wiki/17th_Century seventeenth century] have [[demonstrated]] that [[inertia]]l and gravitational mass are equivalent; this is entailed in the [http://en.wikipedia.org/wiki/Equivalence_principle equivalence principle] of [[general relativity]].

where G is the [[universal]] [https://en.wikipedia.org/wiki/Gravitational_constant constant of gravitation], equal to 6.67×10−11 kg−1 m3 s−2. This is sometimes referred to as gravitational mass (when a distinction is [[necessary]], M is used to denote the active gravitational mass and m the passive gravitational mass). Repeated [[experiments]] since the [https://en.wikipedia.org/wiki/17th_Century seventeenth century] have [[demonstrated]] that [[inertia]]l and gravitational mass are equivalent; this is entailed in the [https://en.wikipedia.org/wiki/Equivalence_principle equivalence principle] of [[general relativity]].

[http://en.wikipedia.org/wiki/Special_relativity Special relativity] provides a [[relationship]] between the mass of a [[body]] and its [[energy]] (E = mc2). As a [[consequence]] of this relationship, the [[total]] mass of a collection of [[particle]]s may be greater or less than the sum of the masses of the [[individual]] particles.

[https://en.wikipedia.org/wiki/Special_relativity Special relativity] provides a [[relationship]] between the mass of a [[body]] and its [[energy]] (E = mc2). As a [[consequence]] of this relationship, the [[total]] mass of a collection of [[particle]]s may be greater or less than the sum of the masses of the [[individual]] particles.

On the surface of the [[Earth]], the weight W of an object is related to its mass m by

On the surface of the [[Earth]], the weight W of an object is related to its mass m by

[[File:Mass2.jpg‎]] ,

[[File:Mass2.jpg‎]] ,

where g is the acceleration due to the Earth's [[gravity]], equal to 9.81 m s−2. An object's weight depends on its [[environment]], while its mass does not: an object with a mass of 50 kilograms weighs 491 newtons on the surface of the Earth; on the surface of the Moon, the same object still has a mass of 50 kilograms but weighs only 81.5 newtons.[http://en.wikipedia.org/wiki/Mass]

where g is the acceleration due to the Earth's [[gravity]], equal to 9.81 m s−2. An object's weight depends on its [[environment]], while its mass does not: an object with a mass of 50 kilograms weighs 491 newtons on the surface of the Earth; on the surface of the Moon, the same object still has a mass of 50 kilograms but weighs only 81.5 newtons.[https://en.wikipedia.org/wiki/Mass]

[[Category: Physics]]

[[Category: Physics]]