Is it possible to numerically solve a differential equation that is composed of the solutions to another numerical differential equation such as
Sol2=NDSolve[g'[x]= G( g[x], f[x] ).....]
where G(x) is the a function of the interpolating function produced from the previous ODE?
I have tried writing the G(x) as by replacing all the f[x]'s with Evaluate[f[x] /. Sol] but I get the error
"NDSolve::ndfdmc: Computed derivatives do not have dimensionality \consistent with the initial conditions."