Answer:
[tex]v=25043.96\ m.s^{-1}[/tex]
Explanation:
As per given conditions we neglect the the air resistance and gravitational pull by the moon.
Height of fall of debris, [tex]h=32000\ km[/tex] (half of earth's radius)
Since the object is under free fall, it will go through the acceleration [tex]\rm g=9.8\ m.s^{-2}[/tex] and will finally impact the ground with a velocity given by:
[tex]v=\sqrt{2g.h}[/tex]
[tex]v=\sqrt{2\times 9.8\times 32000\times 10^3}[/tex]
[tex]v=25043.96\ m.s^{-1}[/tex]