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Is there a formal definition for the apparent weight that does not depend on the situation?

For example, when a body stands on a solid floor the apparent weight is defined via force that floor exerts on the object. This is intuitive since this is exactly what we feel in our feet. When a body is freely falling, it is said that the apparent weight is zero. This is also intuitive since we do not feel any weight in our feet while in free fall. The same applies when the body floats in a fluid.

The floating body situation is especially interesting since the free-body diagram is the same as for the object standing on a solid floor, i.e. buoyancy is equivalent to the normal force. But in the case of the solid floor the apparent weight is not zero, except in some specific situations such as in an elevator accelerating downwards.

Can we say that the apparent weight for a sinking body is the force needed to prevent the body from sinking, i.e. apparent weight plus buoyancy equals weight? If yes, then how does this definition fit the situation in which the object is freely falling?

Marko Gulin
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  • In my experience, the phrase "apparent weight" is used loosely to refer to several different things. There's nobody out there minting official definitions for these kinds of phrases, so you can use it however you want, as long as other people can understand you. – knzhou Jan 03 '22 at 00:28
  • I mean, even forgetting about the word apparent, just the word "weight" by itself already doesn't have a standard definition. I've heard people advocate for weight meaning the mass of an object, the magnitude of its gravitational force, the gravitational force vector, and the normal force vector. – knzhou Jan 03 '22 at 00:29
  • @knzhou Would you mind posting this as an answer? – Marko Gulin Jan 03 '22 at 07:38
  • What you are talking about here is Operational definition of weight,- force which object applies to it's support. – Agnius Vasiliauskas Jan 06 '22 at 21:51

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