At first sight, it may seem that all the information necessary to “reconstruct” the function U(x1−x2) is available already, at least in graphical form: From Figure 4.3.1 you could get the value ...At first sight, it may seem that all the information necessary to “reconstruct” the function U(x1−x2) is available already, at least in graphical form: From Figure 4.3.1 you could get the value of x2−x1 at any time t; then from Figure 8.5.1 you can get the value of K (in the elastic-collision scenario) for the same value of t; and then you could plot U=E−K (where E is the total energy) as a function of x2−x1.