Verified answer

s((t-1)-t)=gt^2/2-g(t-1)^2/2=g/2(2t-1)

s(t)=gt^2/2

2(g/2(2t-1))=gt^2/2

2t-1=t^2/2

4t-2=t^2

t^2-4t+2=0

D=4-2=2

t1=2+корень2

t2=2-корень2<1

t=3.41

Ответ: примерно 3,41с