Answer: t = 1.6s
Explanation: Use Fab 5 equation to solve for t (d is irrelevant so use equation without d)
vi = 16m/s, a = -10m/s^2, vf = 0m/s, t = ?
(Assume up is positive so acceleration is negative!!!)
a = vf - vi / t
-10 = 0 - 16 / t
-10t = -16
t = 1.6s
Hope this helps! :)