Answer:
[tex]1446.7m[/tex]
Explanation:
You need to look at this in 3 separate stages, and then sum thedistance from each stage:
Stage 1)
a=2
t=20
[tex]V_0[/tex]=0
[tex]s=V_0t+\frac{1}{2}g t^2[/tex]
[tex]x=400m[/tex]
We also need to find the final velocity [tex]v=a*t=20*2=40m/s[/tex]
Stage 2)
a=0
v=40
t=20
[tex]x=vt[/tex]
[tex]x=800m[/tex]
Stage 3)
a=-3
[tex]v_0\\[/tex]=40
[tex]v[/tex]=0
[tex]v^=v_0^2 + 2 a x\\0=40^2+2*(-3)x\\x=266.7m[/tex]
So the total distance is [tex]x=400+800+266.7=1466.7m[/tex]
