As per CGPM the official definition of weight is

"The weight of a body is the product of it's mass and acceleration due to gravity."

When I searched for gravity it defined gravity as the fundamental force of attraction acting between any two bodies with non-zero mass. So should not the definition of weight contain "maximum value of acceleration due to gravity?"


1 Answer 1


An object’s acceleration due to gravity is dependent on the gravitational field strength at the object. In general, this is dependent on space and time. This is why an object’s weight is different on, for example, the earth and the moon.

I’m not entirely sure why the maximum value of acceleration due to gravity would be used. Maximum with respect to what?

  • $\begingroup$ I mean sice gravity is the fundamental force of attraction acting between any two bodies with non-zero mass , but while calculating weight we consider the force of attraction between object and earth (if the object is on earth) but various other bodies are also exerting force of attraction on the object. So should not we say that weight is measure of maximum force of gravity experienced by an object , bcoz if we only say force of gravity then there are infinite gravitational forces acting on the object. $\endgroup$ Dec 27, 2019 at 5:54
  • $\begingroup$ @Sameernilkhan But an object's weight is dependent on all gravitational forces. $\endgroup$ Dec 27, 2019 at 6:01
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    $\begingroup$ @Sameernilkhan all of the forces need to be taken into account; in Newtonian physics they add linearly as vectors to give a net gravitational acceleration. In most familiar situations, such as a person standing on earth, the other bodies in the system are either too far away or have too little mass to have a noticeable effect on the gravitational acceleration — everything except the earth’s gravitational field is negligible $\endgroup$
    – DavidH
    Dec 27, 2019 at 7:59
  • $\begingroup$ So why during free fall an object's weight is considered to be zero although it has both mass and acceleration due to gravity? $\endgroup$ Dec 27, 2019 at 10:27
  • $\begingroup$ I think this Wikipedia article explains your confusion pretty well: en.wikipedia.org/wiki/Weightlessness $\endgroup$
    – NDewolf
    Jan 27, 2020 at 10:35

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