Answer:
v = 73.75 m/s
Step-by-step explanation:
It is given that,
A rocket rises vertically, from rest, with an acceleration of 3.2 m/s² until it runs out of fuel at an altitude of 850 m.
Let us assume we need to find the velocity of the rocket when it runs out of fuel.
Let v is the final speed. Using the third equation of kinematics as :

u = 0

So, the velocity of the rocket when it runs out of the fuel is 73.75 m/s