Question

The upward force acting on an object immersed in a liquid called ____ force. It is also called _____.

Answer 1

When an object is immersed in a liquid, then there is a force that acts on the object and this force is equal to the weight of the liquid that is displaced. This force is known as the buoyant force. This force is also known as the upthrust that is offered by the liquid on the object.

Complete step by step answer:
When an object is immersed in some liquid, then the object displaces some of the liquid as it gets immersed. The weight of this dispersed liquid provides a force on the object in the upward direction. This is because, in a liquid column as the depth increases, the pressure also increases due to the overlying fluid.
So when an object is immersed in a fluid, then the bottom part of the object will have more pressure than the top part of the object. Due to this pressure difference, the object feels a force that is acting in an upward direction. This force on the object is called the buoyant force. and this force is also termed as the upthrust.
So the answers will be buoyant and upthrust.

Note:
When the upthrust on an object by a liquid is more than the weight of the liquid, then the object will float on the liquid surface. But when the upthrust is less than the weight of the object, then the object will sink inside the fluid. The center of the buoyancy of any object is the centroid of the displaced volume of the liquid.