Answer:
Height of the rocket be one minute after liftoff is 40.1382 km.
Explanation:

v = velocity of rocket at time t
g = Acceleration due to gravity =
= Constant velocity relative to the rocket = 2,900m/s.
m = Initial mass of the rocket at liftoff = 29000 kg
r = Rate at which fuel is consumed = 170 kg/s
Velocity of the rocket after 1 minute of the liftoff =v
t = 1 minute = 60 seconds'
Substituting all the given values in in the given equation:


Height of the rocket = h



Height of the rocket be one minute after liftoff is 40.1382 km.
First the velocity drops to zero in 1.2 secs. In those seconds it went upwards for 7.2 m, then it went from 87.2 to 0m. x-x0=v0*t+1/2*g*t^2 ergo t=sqrt(2x/g) that is 4.1761 s. Finally the total time required is 5.3761 s