What is the significance of F less than Fmax in the strong nuclear force graph?

[Jimmy87]

Homework Statement

http://www.boredofstudies.org/wiki/images/b/bb/Sci_phys_quanta_strong_force.png
I had a question where I was given the strong nuclear force graph and asked to add the electrostatic force to the graph. It was a graph showing the forces between two protons. It was a three mark question. 1 mark is given for a shape that resembles 1/r^2. 1 mark is for making sure it stays above the x-axis. The final mark is for making sure it crosses the strong nuclear force for F less than Fmax. It is this final mark I am unclear about. What does it mean for F less than Fmax? Why does it have to cross at this particular point?

Homework Equations

None

The Attempt at a Solution

Read around textbooks and fully understand first two marking points.

 

[mfb]

Fmax could be the maximal attractive force, but I don't see why the two forces should cross below that (as absolute values). Maybe they just have to cross somewhere.

 

[Jimmy87]

Fmax could be the maximal attractive force, but I don't see why the two forces should cross below that (as absolute values). Maybe they just have to cross somewhere.

Thanks. Is there any significance of the electrostatic crossing the strong nuclear? I just don't see why this is a specific marking point for that question? What would be the problem drawing the electrostatic shifted to the right so that it doesn't cross the strong nuclear force line at all?

 

[mfb]

Well, it does cross it, but at that point the electromagnetic force is not an easy 1/r^2-potential any more so this simplified picture breaks down anyway.