When does the slosh-dynamics problem become useful?

A)
When the liquid is non-Newtonian
B)
When the liquid has a free surface
C)
When the liquid has no free surface
D)
When the material stored inside the tank is thixotropic

Correct Answer :   When the liquid has a free surface


Explanation : The liquid stored inside the tank needs to have a free surface for slosh-dynamics to be applied. Propellant slosh in aircraft and rocket tanks are some examples of slosh dynamics problems.