Martina hits volley ball with an upward velosity of 13

Question

M/s 1meterabove the grund. How long will it take for the ball to hit the ground.

Answer 1

Vi = 13 m/s
Hi = 1.0 m

h = Hi + Vi t - 4.9 t^2
0 = 1 + 13 t - 4.9 t^2

now it is algebra

4.9 t^2 - 13 t - 1 = 0

t = [ 13 +/- sqrt (169 + 19.6)/9.81
use positive time :)

t = 2.73 seconds
(good hit, wow ! )