By kinematics equation we will say
displacement of object = 8000 m
acceleration = 9.8 ms^2
initial speed = 0
[tex]v_f^2 - v_i^2 = 2 a d[/tex]
[tex]v_f^2 - 0 = 2*9.8 * 8000[/tex]
[tex]v_f^2 = 156800[/tex]
[tex]v_f = 395.98 m/s[/tex]
so it will move with speed 395.98 m/s