Help please
Rocket-s-Euler.sm (87.43 KiB) downloaded 825 time(s).

EK45 was Deified by Mathematica
Working code included.
Jean

Rocket-s-Euler.sm (122.44 KiB) downloaded 811 time(s).

Thanks.
I have corrected myself
Rocket-s-Euler-RK.sm (87.35 KiB) downloaded 743 time(s).
New question
Why this not works
Rocket-s-Euler-RK-full.sm (88.8 KiB) downloaded 760 time(s).

Your RK does work! Your Euler doesn't because you have defined the acceleration term to have two input variables, but only call it with one in the Euler routine!

Rocket-s-Euler-RK-full.sm (89.85 KiB) downloaded 776 time(s).

Wrote

Your RK does work! Your Euler doesn't because you have defined the acceleration term to have two input variables, but only call it with one in the Euler routine!

Tanks!

Send me please the corrected file.

Wrote

Wrote

Your RK does work! Your Euler doesn't because you have defined the acceleration term to have two input variables, but only call it with one in the Euler routine!

Tanks!

Send me please the corrected file.

I've now added the corrected file to my earlier reply.