Given,
The initial velocity of the rocket is 60 feet per second.
The model for the height of the rocket after t seconds is,
[tex]h=60t-16t^2[/tex]When the rocket returns to the gorund, its height becomes 0.
Taking the equation of height when the rocket returns to the gorund,
[tex]\begin{gathered} 60t-16t^2=0 \\ (15-4t)=0 \\ \text{15-4t=0} \\ \text{t=}\frac{15}{4} \\ t=3.75 \end{gathered}[/tex]Hence, the rocket in the air before it return to the ground for 3.75 seconds.
