it's take same amount of time to go up as go to down. -1.1s is from ground level so when 1.9s-1.1s its where they meet and point is 0 and the diffrence is time from the top of the arc to ground,
ah I see now so Vf=Vi+at where Vf=0 Vi 4m/s and a=9.8 m/s t=? so
t= (Vf-Vi)/a t= -4m/s / -9.8 m/s^2
t= .41s
from top to the ground or I should 1.9 s- 1.1s = .8s and that's time from top to ground ?
for b) i tried Yf= yi + Viyt + 1/2 at^2
0=10m +4m/s*t + 1/2(9.8m/s)t^2
t= 2*(10m+4m/s)/9.8 m/s
t= 28/9.8s
t= 2.9s
t is time to reaches the ground from the top
Or i should assume my Yi is 0?