Question

An infinite mass of homogeneous incompressible fluid acted upon by no forces is at rest, and a spherical portion of the fluid is suddenly annihilated. What will happen to the fluid? A) It will start moving in a random direction. B) It will remain at rest. C) It will accelerate in the opposite direction of the annihilation. D) It will expand in all directions.

Answer 1

In a situation where a portion of an incompressible fluid is eliminated and no external forces are acting, the fluid will stay at rest due to Newton’s First Law. The fluid won’t move or fill up the void left behind by the eliminated portion.

Step-by-step explanation:

The question deals with a homogeneous incompressible fluid at rest, from which a spherical volume is suddenly removed or 'annihilated'.

Let's consider Newton’s First Law: A body at rest will remain at rest unless acted on by a net external force. We are told that no forces are acting upon the fluid. Therefore, according to this principle, the fluid would remain at rest even after the portion is removed. The fluid won't start moving randomly, it won't accelerate in the opposite direction of the removal, and it won't expand in all directions.

So the correct answer is B) it will remain at rest. The remaining fluid will stay exactly where it is and the gap created by the annihilation of the spherical portion will just remain as an empty space.

Learn more about Newton’s First Law