1.由题,v=3.5a,不妨设a=2,则v=7
x(t)=vt-0.5at^2=7t-t^2
x1=x(1)=6
x2=x(2)-x1=4
x3=x(3)-x(2)=2
x1:x2:x3=3:2:1
2.
x(1):x(2):x(3)=3:5:6