Momentum of a system isn't always constant. What condition ...

[sheilaspns]

Momentum of a system isn't always constant. What condition assures that momentum is conserved for a system?
 
  What will be an ideal response?

Question 2

Uh-oh, the malicious eight-dimensional alien beings are back. This time, imagine that they suddenly changed nature so that neither the uncertainty principle nor the exclusion principle applied to electrons.
 
  What would happen almost immediately to atoms? A) Atoms would annihilate each other, releasing huge amounts of energy.
  B) Atoms would be immediately ionized.
  C) Nothing; atoms would be unaffected by this change.
  D) Electrons would fall into the nuclei of atoms.

[kmb352]

Answer to Question 1

Momentum is conserved for an isolated system; i.e., if the net external force acting on the system is zero.

Answer to Question 2

D