Question

Bob shoots an arrow straight up into the air at 78.5 m/s.
1)What is the maximum height of the arrows flight?
2)How long is it in the air?

Answer 1

1. hmax = V^2-Vo^2)/2g.
hmax = (0-6162.25)/19.6 = 314.4 m.

2. Tr = V-Vo)/g = (0-78.5)/-9.8 = 8 s. =
Rise time.
Tf = Tr = 8 s. = Fall time.
Tr + Tf = 8 + 8 = 16 s. = Time in air.