Answer:
78.1 m/s
Step-by-step explanation:
The time it takes to fall from 252 meters above the ground is about ...
252 = 4.9t^2
√(252/4.9) = t = 7.1714 . . . seconds
Then the horizontal speed is ...
speed = distance/time
speed = 560 m/(7.1714 s) = 78.088 m/s
The horizontal speed is about 78.1 m/s.
_____
That's about 281 km/hour.