Answer:
S = 1/2 a t^2 distance covered by falling body from speed = 0
300 = 1/2 a 10^2
a = 600 m / 100 s^2 = 6 m/s^2
v = a t = 6 m/s^2 s * 10 s = 60 m/s speed after 10 sec
S2 = v t + 1/2 a t^2
S2 = 60 m/s * 10 sec + 3 m/s^2 * 100 s^2
S2 = 600 m + 300 m = 900 m