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Density and an Immersed Block

awibroe
14-Alexandrite

Density and an Immersed Block

So today's challenge...

So I have a problem to which I am given the answer. The real issue is that I need to understand how the answer is derived.

I have attached a word document which gives the problem and the solution. I understand the first steps taken in that the resultant forces have to be at equilibrium as the block immersed (and floating) in the 2 liquids is at rest.

i.e EqualF.PNG

Then by factoring g and A out of the RHS and dividing both sides by gA I am left with:

Equal1.PNG

Then as the question calls for the ratio h1/h2, I believe that I multiply out the LHS then divide both terms on both sides by h2 to get:

Equal3.PNG

I know that the example in the question factors the LHS but I don't believe this is necessary. The problem I am then having is that the question's given answer in the attached document seems to suggest the ultimate answer is:

Answer.PNG

however, from everything I have tried algebraically by hand, the likes of Cymath / wolfgram Alpha and Mathcad itself the answer is suggested to be:

MathCADA.PNG

Am I going mad somewhere or am I going to need to be brave enough to question the professor who issued the model answer?

Thanks to anyone that can put me out of my misery!

Andy

ACCEPTED SOLUTION

Accepted Solutions
LucMeekes
23-Emerald III
(To:awibroe)

You probably missed the minus-sign just before the ratio.

That makes the rho and rho2 swap places if you bring it in.

Luc

View solution in original post

4 REPLIES 4
awibroe
14-Alexandrite
(To:awibroe)

The attachment didn't seem to work. This is the question/ answer:

Question.PNG

LucMeekes
23-Emerald III
(To:awibroe)

You probably missed the minus-sign just before the ratio.

That makes the rho and rho2 swap places if you bring it in.

Luc

awibroe
14-Alexandrite
(To:LucMeekes)

‌A bit embarrassing but yes that was my omission...

cheers!

-MFra-
21-Topaz II
(To:awibroe)

A bit of hydrostatic?

Hydrostatic.jpg

I apologize for some mistakes and for  a not perfect translation.

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