UPTHRUST咩情況下會有

Q: UPTHRUST 點PRODUCE IT/咩情況下會有

Upthrust is, in fact, the buoyance experienced by an object when it is immersed in a fluid. It arises because of pressure difference between the top and bottom of the object. Since the pressure acting at the bottom is normally greater than that acting on the top, the diference in pressure thus produces a thrust (which acts in the upward direction, hence the name "upthrust") that pushes the object upwards.

Q: 仲有佢5係有FLUID就有咩?
Yes, upthrust exists in a fluid. But according to Archimedes Principle, the upthrust is equal to the weight of fluid displaced. Hence, the density of the fluid is a major factor that determines the magnitude of upthrust.

Q: 5係AIR都有咩,點會UPTHRUST=0
Object immersed in air also experienced an upthrust. However, because of the low density of air as compared with that of liquid fluids, the upthrust acting on an object in air is generally negligible .