A cube of oak with sides 15cm long floats upright in water with 10.5cm of its depth submerged. What is the density of the oak?

Answer 1

The weight of the oak equals the weight of a 15 x 15 x 10.5 cm block filled with water (since that is the buoyancy force). That is the displaced volume of water.

The density of the block is
(water density)x(15 x 15 x 10.5)/(15 x 15 x 15) = 1 x 10.5/15
= 0.70 gm/cm^3

Answer 2

Part inside = 10.5 /15
And inside also equal to d1/d2
And u get the answer 0.70
G/cm3