Setting h=0 and solving for t we get:
[tex]\begin{gathered} 0=-16t^2+676, \\ 16t^2=676, \\ t^2=\frac{676}{16}, \\ t^2=42.25 \\ t=\pm\sqrt[]{42.25}. \end{gathered}[/tex]
Since t<0 does not have real meaning, we get that:
[tex]t=6.5.[/tex]
Answer: 6.5 seconds.
