The height that a model rocket launched from earth can reach can be estimated by assuming that the burn time is short compared to the total flight time, so for most of the flight the rocket is in free-fall. (This estimate neglects the burn time in calculations of both time and displacement). For a model rocket with specific impulse Isp=100s, mass ration m0/mf = 1.2, and initial thrust-to-weight ratio r0=5. Estimate a) the height the rocket can reach and b) the total flight time. c) Justify the assumption used in the estimates by comparing the flight time from part (b) to the time it takes for the fuel to be spent. I never heard of impulse Isp, I know it is measured in seconds so it has to do with time. Initial thrust-to-weight ratio?? This is really torturing; I had to go to chapters we didn’t cover where they discuss r0= Fth/(m0g), and Isp = Fth(Rg). I can't get the height from The rocket equation (vertical componets). For b) The only equation that has time t in it is the (velocity of the rocket, vertical component),but again there is no Isp nor r0 in it. I am completely lost!