A cube of some substance floats

[cashflow]

Homework Statement

A cube of some unknown material floats in a pool of mercury. 43% of the cube is above the surface. Find the density of the cube.

Homework Equations

Fb=pVg
d=m/V

The Attempt at a Solution

So I Googled the density of mercury and found that it is 13,594 kg/m³. I also know that 57% of the cube is underwater.

mg=pVg
m=pV
m=p(.57V)

d=m/V
d=p(.57V)/V
d=.57p_Hg

Is that correct?

 

[schroeddycat]

That is correct. If an object displaces 57% of the weight of mercury then that means it's own weight is 57% of that of the weight of mercury in the same volume. This means then that it's density is 57% that of mercury.