Another seemingly very easy question (Energy)

[PolyFX]

Homework Statement

The diagram below is a graph of potential energy vs. interatomic separation for a particular diatomic molecule (that is, a molecule consisting of two atoms).

For the energy level shown on the graph, imagine drawing a line whose length represents the kinetic energy when the interatomic separation is r0. This line runs from where to where?

Homework Equations

K+U=E?
0.5Ks^2=E

The Attempt at a Solution

I always have problems analyzing graphs. I got the latter parts of this question correct which involved doing calculations. However, I can't seem to get this one. The only reasonable answer I can come up with is from 1 to 2 since that would make the molecule unbound and allow it to separate (break apart). Any help on this question would be much appreciated.

 

[kuruman]

If you were to draw the total energy on the same graph as a function of r, what would it look like?

 

[kerimek]

Your reasoning is correct. The line would run from point 1 to point 2 on the graph, representing the kinetic energy at the given energy level when the interatomic separation is r0. This would indicate that the molecule is unbound and can break apart at this energy level. This also means that the molecule has enough energy to overcome the attractive forces between the atoms and separate into two individual atoms.