Quadratic model for the rocket

Equation for flight rocket is h(t) = -110t^2 + 2009.3t + 0.9 where h(t) is the height in meters above the ground after t seconds.

** What is the practical domain of the function. Explain your answear.**

Does the model seem realistic. Justify

One user of forum said [0, t] where h(t)=0

Well i am not pretty sure. i think that practical domain is 0=<t<=18.23

where 18.23 is a root. Please correct me if i'm wrong

And i want apologize that i didn't start new thread with another problem!!!