Question

how to proove Archimedes principle????..... answer very quickly

Answer 1

The Archimedes' Principle states that when a body is partially or completely submerged in a fluid, it has an apparent loss in its (real) weight. This loss in weight is due to the upthrust of the fluid. The weight apparently lost is equal to the weight of the fluid which was displaced by the immersion of the part of the body into the fluid.

We call it 'apparent' loss because the weight of the body immersed remains the same, but the when measured in a fluid, the body feels lighter due to the buoyancy of the liquid. 

Here is an experiment to prove the Archimedes' Principle.
We need the following apparatus for this experiment:
•Eureka can
•Beaker
•A metal cube
•Spring balance.

Take the metal cube a suspend it in air using your spring balance. Note down the reading of the spring balance with the cube in air. Let this weight be 'W₁'

Then, take the cube and immerse it into the Eureka can which should have water filled up to its spout. Place a beaker near the spout of the eureka can to collect overflowing water.

Note the reading in the spring balance again and, after immersing the cube in water. Let it be 'W₂'. Now, you have the weight of the cube in the air and inside water. When you place the metal cube in the Eureka can, some water overflows out into the beaker. Collect it and keep it aside.

You will notice that the W₁ is heavier than W₂. The W₂ is the weight of the metal cube in water, and it is less heavier because of upthrust of water.

Now, measure the weight of the water collected in the beaker. When compared, you will find that the weight lost by the cube (in water) (W₁ - W₂) will be equal to the weight of water in the beaker, i.e, the weight of the water displaced by the cube.