Did a question about this a few weeks ago, but I thought I might do another, as I don't quite get, what is going on. The relationship: v=vex * log(m0/m(t)) tells us that a rocket will attain greater and greater acceleration as time goes. However, when I try to simulate this in Matlab I get the curve attached (time versus velocity). Anyone got an idea, what could be wrong? It looks similar to that of a ln-curve, but shouldnt it look differently. If someone is into Matlab programming, can they please look at what I've failed in my (short!) script (attached).