Question

Which among the following provides the third principle in fluid mechanics?

(a) Conservation of mass

(b) Conservation of linear momentum

(c) Conservation of Heat

(d) Conservation of volume

I had been asked this question in an interview.

This intriguing question originated from Specific Force in chapter Non Uniform Flow in Channels of Fluid Mechanics

Answer 1

Correct choice is (b) Conservation of linear momentum

For explanation: In fluid mechanics, the third principle is given by the conservation of linear momentum. It is in addition to the continuity of mass and conservation of energy. They are mostly seen in channel flow problems.