Respuesta :

gmany
[tex]v=\sqrt{64h}=\sqrt{64}\cdot\sqrt{h}=8\sqrt{h}[/tex]
[tex]\text{substitute the value of h=84 ft.}\\\\v=8\sqrt{84}\approx8\cdot9.165\approx73.32[/tex]
[tex]\boxed{Answer:\ B.\ 73.32\ ft/sec}[/tex]