Question

Define the buoyant force. Name two factors on which buoyant force depends.

Answer 1

Hint: In this question we have been asked to define buoyant force. We have also been asked to determine two factors on which the buoyant force depends. Therefore, to answer this question, we shall first describe the buoyant force. We shall study the causes of buoyant force. This shall help us in naming the two important factors on which the buoyant force depends. We know that buoyancy is the force that causes objects to float in the liquid.

Complete step-by-step solution
Buoyancy also is known as upthrust is an upward force that opposes the weight of the body partially or fully immersed in the fluid. The buoyant force is applied to the object by the fluid in which the object is immersed. We know that the pressure of a fluid in a column increases as the depth of the column increases. This is due to the increase in the weight of fluid due to an increase in depth. Therefore, if an object is immersed in the fluid, the top surface of the object will be at a lower pressure than the bottom surface of the object. This pressure difference will result in a net upward force. This force is known as the buoyant force.
According to the Archimedes principle, the magnitude of the buoyant force is proportional to the pressure difference. He also stated that the magnitude of the buoyant force is equal to the weight of the fluid that would occupy the same volume as the object immersed in it. Therefore, if an object of higher density than the fluid is immersed in the fluid, the object will sink and vice versa.
Therefore, from this, we can say that the two main factors for buoyant force are the volume of fluid displaced by the object and the density of the fluid.

Note: The buoyancy force was discovered by Archimedes. He stated the principle that the weight of the fluid displaced is directly proportional to the volume of fluid displaced. The buoyancy force is an upward force meaning it always tends to push the object out of the fluid in an upward direction. The cause of buoyant force is the pressure that is applied to the object by the fluid the object is immersed in.