1. The problem statement, all variables and given/known data 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? 2. Relevant equations None 3. The attempt at a solution Read around textbooks and fully understand first two marking points.