I have developed the code for the assignment. I think there are several parts that are ambiguous:
1- It is not clear from the figure that what is the propellant burn rate at t=5. Is it 20 or 0?
2- When using Euler method, f(u) has to be evaluated at t=n (and not t=n+1 or n+1/2).Is it right?
3- Using the dt=0.1 of the assignment, there is no discrete point with h=0 to find when the rocket impacted the ground. Shall I use linear interpolation to find associated time and velocity of h=0 point?
Vmax is: 237.2
t @ Vmax is: 5.1
h @ Vmax is: 546.73
hmax is: 1372.04
t @ hmax is: 15.9
but the system doesn't approve them.