Rocket acceleration, how high does it go?

[JackDW]

A model rocket is fired upward. The rocket's average initial acceleration is 44.5 m/s2 until the fuel burns out in 0.835 s. How high does the rocket go? Ignore the effects of air friction.

I was thinking about using the equation x=x(initial)+V(initial)*t+1/2at^2

 

[Simon Bridge]

Welcome to PF;
Before thinking about the equation to use, start out by describing the physical processes the rocket will go through. After the fuel burns out, what happens? i.e. can you sketch a v-t diagram for the motion?