Answer:
t1 = 2.2 s
t2 = 11.5 s
Step-by-step explanation:
The general quadratic formula for these cases is
h(t) = h0 + v*t + 0.5*a*t^2
Where
a = the acceleration of the body. In this case, since the arrow is going upwards, we take the acceleration of the gravity.
a = -32.2 feet/s^2 = -9.8 m/s^2
v = the velocity
v = 220 ft/s
h0 = the initial distance. We assume it launched from ground
h0 = 0
h(t) = - 16.1*t^2 + 220*t
See, attached picture
When the height h = 400 ft
- 16.1*t^2 + 220*t = 400
t1 = 2.159 s ≈ 2.2 s
t2 = 11.505 s ≈ 11.5 s
