Upthrust or buoyant force arises due to the differences in pressure acting on the submerged object. The fluid exerts pressure on all sides of the object, and the pressure is greater at greater depths. The pressure difference between the top and bottom of an object creates an upward force (i.e., upthrust) that opposes the weight of the object.
Upthrust acts on the body in upward direction at the centre of buoyancy (i.e., the centre of gravity of the displaced liquid).
