Question

initial speed with which water strikes the ground.

Answer 1

Let the discharge velocity be v

So $v=\sqrt{2gh}=\sqrt{2\times 10\times 5}=10m/s$

Let say it strikes the ground with $v_1$ velocity

So $v_1^2-v^2=2gH$

$v_1^2={10}^2+2\times 10\times 5$

$v_1=14.14m/s$