Question

What is the cause of upthrust?At which point it can be considered

Answer 1

Answer:

upthrust or buoyancy is an upward force acting on an object that is fully or partially immersed in a fluid.

buoyant force = weight of the fluid displaced by the object

= mass of the fluid × gravitational acceleration (g)

= density of the fluid × volume of the fluid displaced × (g)

=density of the fluid × volume of the object that is in the fluid (immersed) × g

i.e also apparent weight = real weight - upthrust

* Buoyant force or upthrust can only be considered when the object is fully or partially immersed in the fluid.

if the object fully floats without displacing any volume of fluid the upthrust is equal to zero. therefore it keeps floating due to surface tension.