Because jumping 0.8m from10m height can be regarded as a free fall from10.8m height.

So: t = (vt-v 0)/g (t and 0 after v are subscripts)

T= 14/9.8= 1.43 seconds.

Plus the initial 0.8 m: slow down and vomit.

S = 1/2gt 2 calculates that t is 0.40s, so the total time is1.83s..

(2)

Because it is a free fall, the change is 9.8m/s 2.

(3)

S= 1/2gt^2

S = 5.8m

g=9.8m/s^2

Substitute and calculate t= 1. 1.