Calculating Density of Oil Using Buoyant Force Formula | Homework Help

[mikefitz]

Homework Statement

Buoyant force. A block of wood floats in
oil with 90.0% of its volume submerged. What
is the density of oil? The density of the block
of wood is 0.67 g/cm3.

Homework Equations

buoyant force = pgV

The Attempt at a Solution

p(oil) V(oil)=p(h20) V(h20)

p(oil)= p(h20) V(h20) / V(oil)

i know that the V(oil) displaced is equal to .9V(h20)

so, p(oil) = .67 V(h20) / .9 V(h20)

do the terms 'V9h20' simply cancel, leaving me with .67/.9? Thanks

 

[billiards]

h20? hmmm where did you get that from,I hope you don't mean H₂O because my friend this problem has no water to be seen!

You need to use the fact that the block is in equilibrium, thus the buoyancy force is equal and opposite to another force... hmmmm what could that be. It's really easy, have another go at a solution.

 

[mikefitz]

gah i was half working on another problem while typing this one out, sorry for the stupid typo; thanks for the response