Answer :
Answer:
0.75 second
Explanation:
The equation is
[tex]h = 16t^{2}+64 t + 16[/tex]
Let t be the time when it is at 73 feet. Substitute, h = 73 in the above equation and then find the value of t.
[tex]73 = 16t^{2}+64 t + 16[/tex]
[tex]16t^{2}+64 t-57=0[/tex]
[tex]t=\frac{-64\pm \sqrt{64^{2}+4\times 16\times 57}}{2\times 16}[/tex]
[tex]t=\frac{-64\pm 88}{32}[/tex]
Take positive sign
t = 0.75 second