When does an object experience upthrust?

Upthrust, also known as buoyant force, is experienced by an object when it is submerged in a fluid, which can be either liquid or gas. This upward force arises due to the pressure differences on the top and bottom surfaces of the object when it is in a fluid.

When an object is submerged, the fluid exerts pressure on it from all directions, but this pressure increases with depth. The pressure at the bottom of the object is greater than the pressure at the top, resulting in a net upward force, or upthrust. This phenomenon occurs whether the fluid is water, oil, air, or any other fluid, as long as the object is in it.

In contrast, when an object is on land, in a vacuum, or floating in air, it does not experience upthrust in the same significant way. On land, the object is supported by the ground, while in a vacuum, there are no fluids present to create buoyant forces. Similarly, while air does exert a force, it is usually not sufficient for most objects to experience a noticeable upthrust unless they are particularly lightweight or designed to float, such as balloons. Thus, the most accurate scenario depicting the experience of significant upthrust is when