# Deriving relationship about water not falling down from a hole under a fast flowing stream [closed]

A gutter is tilted from an angle of $$\theta$$ with respect to earth. There is a hole on the gutter from a distance of $$l$$ (m) from the top of a gutter. What is the speed of the water that should flow above the hole so that water will not drop down from the hole. (Assume speed of the water stream in the gutter at the top is zero).

I can't identify the forces and principle behind this phenomenon to derive an relationship. I need to derive an equation. Variables that may affect are $$\theta$$, $$l$$, $$r$$ (radius of the hole), pressure difference (Bernoulli) etc. Can someone please help me to understand how water would not fall down and to derive an equation?

## closed as off-topic by Kyle Kanos, John Rennie, ZeroTheHero, Jon Custer, user191954 Nov 29 '18 at 14:41

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• Maybe the "top of the gutter" is where the gutter is horizontal, and it bends down at an angle $\theta$. Then the water wouldn't go in the hole if it was going fast enough because it would shoot out into the air. – Ben51 Nov 29 '18 at 3:35