Mechanical properties of solids questions

[Mandavi]

Homework Statement

Intermolecular forces are
1- Attractive only
2-Repulsive only
3-Long-range
4-Short-range

Homework Equations

The 1st and 2nd options are not valid as the nature depends on the distance between the molecules.

The Attempt at a Solution

The answer given is short-range.How is that?Even,at infinity,the force does not become zero as even then,attractive forces should act.Or is it so,because intermolecular distances are measured on a very small scale and therefore,they are not valid for long distances?

 

[Mandavi]

This is another question from the same topic.
"In a solid,the kinetic energy of molecules is less than the magnitude of their potential energy."
How did we come to this conclusion?I know it is true for an atom,but why do we say this for molecules of a solid too?