Originally Posted by
Cragyon
Density = Mass / Volume
or
p = m / V (a)
Density change
E = - dp / (dV / V0)
= - (p1 - p0) / ((V1 - V0) / V0) Equation A
Where:
E = bulk modulus - liquid elasticity (N/m2)
The minus sign corresponds to the fact that an increase in the pressure leads to a decrease in volume.
With (A) - the final volume after pressure change can be expressed as
V1 = V0 (1 - (p1 - p0) / E) (Ab)
Combining (Ab) with (a) - the final density can be expressed as:
ρ1 = m / (V0 (1 - (p1 - p0) / E))
These are the equations you need to calculate the amount of pressure you need to float an object..