- #1

gunblaze

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I have 2 liquids, mercury and water together in the beaker.

Assuming both liquids are non mixable, the water, with a lower density, will be at the top while mercury will be at the bottom.

Now, I push a block into the water and it floats at halfway between the mercury and the water. I need to find the height of X1, which is the height of the block submerged in the mercury.

Now, my friend's solution to find X1 is to equate the

**upthrust by the mercury**to the

**weight of the block and the upthrust by the water**. since the block is floating.

However, the solution gives the

**upthrust by both the water and the mercury**= to the

**weight of the block**.

The difference here is that my friend actually think that the upthrust by the water is acting downwards same as the weight while the upthrust by the mercury is acting upwards.

Well, for me, I told my friend that if we were to think of archimedes principle, upthrust is equals to the weight of the water displaced by the block and so, the solution is right.

However, i can't deny the fact that my friend is also right to a certain extent. Since the pressure by the water molecules at the top will exert a downward pushing force on the block.

So who's right, who's wrong. Appreciate it if anyone can help clarify this.