What describes the relationship between upthrust and weight for an object to float?

For an object to float, the upward force known as upthrust (or buoyant force) must be equal to the downward force of weight acting on the object. This balance of forces is crucial to achieve a state of equilibrium. When these two forces are equal, the object neither sinks nor rises, allowing it to remain at rest at a certain level in the fluid.

When upthrust equals weight, the object is in a stable position. If upthrust was greater than weight, the object would rise in the fluid until the forces balance. Conversely, if upthrust was less than weight, the object would sink. It's important to note that weight is the force due to gravity on the object, while upthrust is the force exerted by the fluid that opposes this weight. Hence, the correct relationship that allows for floating is that upthrust must equal weight.