Buoyant Force - Issue with minor details

[Vybe]

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Hey guys,

Simple issue, but can't seem to wrap my head around it.

What is the purpose of knowing the value of the weight in fluid an object displaces verses the volume in fluid an object displaces? I keep seeing weight and volume being used interchangeably and I need to get a better solidified grasp on this....

What are its distinguishing uses between the two?

Thanks for any help!!

 

[gettheleadout]

The magnitude of the buoyant force on an object is equal to the magnitude of the gravitational force (i.e weight) on the fluid displaced by the object. The volume of the fluid displaced can often be easily found by either knowing the volume of the object (for submerged objects) or by measuring the increase in fluid level (for both submerged and floating objects). By knowing the density of the fluid, the volume can be converted to a mass and then the weight of that mass can be easily found. Because mass directly determines weight and density is constant for incompressible fluids, the statement that buoyant force is determined by the volume of the fluid displaced is equally as correct as that the buoyant force is determined by the weight of the fluid displaced.

The two statements exist because the weight equals the buoyant force (providing a mathematical representation) and the volume is the practically accessible means with which to calculate that weight.

 

[Dipraman]

Hey guys,

Simple issue, but can't seem to wrap my head around it.

What is the purpose of knowing the value of the weight in fluid an object displaces verses the volume in fluid an object displaces? I keep seeing weight and volume being used interchangeably and I need to get a better solidified grasp on this....

What are its distinguishing uses between the two?

Thanks for any help!!

If an object is partially submerged in fluid then the weight of the fluid is equal to the weight of the fluid displaced.

If it is fully submerged in the liquid then the volume of the fluid displaced is equal to the volume of the object.


Anybody feel free to correct me if I am mistaken

 

[gettheleadout]

If an object is partially submerged in fluid then the weight of the fluid is equal to the weight of the fluid displaced.

If it is fully submerged in the liquid then the volume of the fluid displaced is equal to the volume of the object.


Anybody feel free to correct me if I am mistaken

Assuming the fluid in which an objects is floating or submerged is incompressible (e.g. water), the fluid's volume and weight (mass) are directly related and distinguishing between them is not useful.

The magnitude of the buoyant force on any (partially or totally) immersed object is equal to the weight of the fluid displaced; this is Archimedes' Principle.

You've typoed and conflated the weights in your first statement, but there is a distinction between the cases. For all floating objects, the buoyant force is not only equal to the weight of the displaced fluid but also equal to the weight of the floating object. Such a generalization cannot be made for submerged objects.