Solution
Given
[tex]h(t)=-16t^2+5t+15[/tex]
Set h(t) = 0
[tex]\begin{gathered} \Rightarrow-16t^2+5t+15=0 \\ \\ \text{ Using quadratic formula } \\ \\ \Rightarrow t=\frac{-5\pm\sqrt{5^2-4(-16)(15)}}{2(-16)}=\frac{5\pm\sqrt{985}}{32} \\ \\ \Rightarrow t=1.14\text{ sec} \end{gathered}[/tex]
Hence, the ball will hit the ground in 1.14 sec
