解:[1]∵x=0.5gt2∴t=5∴v=gt=50(m/s)∵t'≈3.15(s)∴x=v0t+0.5at2=86.55(m)∴X=x+x'=125+86.55=211.55(m)[2]∴T=t+t'=5+3.15=8.15(s)