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