we will use one of the kinematic equations :
d = u*t+0.5*a*t²
in which : d : distance
u : initial velocity
a : acceleration
t : time
after substitution :
initial velocity = 0 m/s (from rest)
2.8 = 0*t+0.5*7.14*t²
2.8 = 3.57*t²
t² = 0.7843
after square root
t = 0.885615 s
I hope this answer will help