Answer
(a) 8.6 km/h
(b) 14.7 km/h
Work Step by Step
(a) We use $P=10000$:
$10000=15.6v^{3}$
$v^{3}\approx 641.02$
$v\approx 8.6$
So the wind would have to blow at a speed of 8.6 km/h.
(b) We use $P=50000$:
$50000=15.6v^{3}$
$v^{3}\approx 3205.13$
$v\approx 14.7$
So the wind would have to blow at a speed of 14.7 km/h.
