Answer
The correct answer is:
(a) conservation of mass
Work Step by Step
We can write the continuity equation like this:
$\rho~A_1~v_1 = \rho~A_2~v_2$
$A$ is cross-sectional area
$v$ is velocity
Therefore, the expression $~~A~v~~$ is the volume flow per unit time. Then $~~\rho~A~v~~$ is the mass flow per unit time. The form of the continuity equation shows that the rate of mass flow is conserved.
The correct answer is:
(a) conservation of mass
