Newton

d = 0.5at^2
30m = 0.5 * 9.8 m/s^2 * t^2

4.9 t^2 = 30
t^2 = 6.122
t = 2.47 s

v= at = 9.8 m/s^2 * 2.47 s = 24.25 m/s

Energy

PE = KE

MGH = 0.5MV^2 (cancel M)

GH = 0.5V^2
9.8 * 30 = 0.5 V^2
294 = 0.5V^2
V^2 = 294/.5 = 588
V = 24.25 m/s

No matter how you do it, the answer is always the same. (It would be really bad if it was not!)

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