Answer:
t = 1 s to reach its maximum height.
Step-by-step explanation:
The function that represents the height of the rocket after s seconds is given by :
[tex]h(s)=-3s^2+6s+45[/tex] ...(1)
For maximum height,
[tex]h'(s)=0\\\\-6s+6=0\\\\s=1[/tex]
It is the time the rocket will take. So, the ball will take 1 second to reach its maximum height.