Help please
Rocket-s-Euler.sm (87 KiB) downloaded 60 time(s).

EK45 was Deified by Mathematica
Working code included.
Jean

Rocket-s-Euler.sm (122 KiB) downloaded 67 time(s).

Thanks.
I have corrected myself
Rocket-s-Euler-RK.sm (87 KiB) downloaded 55 time(s).
New question
Why this not works
Rocket-s-Euler-RK-full.sm (88 KiB) downloaded 52 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 KiB) downloaded 65 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.