Answer:
t = 0.55 s and t = 1.14 s
Explanation:
as we know that height in terms of time is given as
[tex]h = 3 + 27t - 16 t^2[/tex]
now we have to find the time at which its height is h = 13 ft
so here we can say
[tex]13 = 3 + 27 t - 16 t^2[/tex]
[tex]16 t^2 - 27 t + 10 = 0[/tex]
[tex]t = \frac{27 \pm \sqrt{27^2 - 4(16)(10)}}{2(16)}[/tex]
[tex]t = \frac{27 \pm 9.43}{32}[/tex]
[tex]t = 1.14, 0.55[/tex]
so it will be at h = 13 ft height at t = 0.55 s and t = 1.14 s
