- #1
fog37
- 1,568
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Hello Forum,
The speed of water exiting from a side narrow hole at depth h in a large bucket is given by ##v=\sqrt{2gh}##.
This result is obtained applying Bernoulli's equation along a streamline that goes from the top free surface to the drain on the side of the bucket at depth h.
Thanks!
The speed of water exiting from a side narrow hole at depth h in a large bucket is given by ##v=\sqrt{2gh}##.
This result is obtained applying Bernoulli's equation along a streamline that goes from the top free surface to the drain on the side of the bucket at depth h.
- The water speed at the free surface is practically zero.
- The pressure at the free surface is ##p_{atm}. This pressure pushes on the liquid in the downward direction.
- The liquid pressure at depth h since the liquid, at the same depth as the drain, is ##p = p_{atm} + \rho g h##. But in the application of Bernoulli's equation we take the pressure at the hole to be the atmospheric pressure ##p_{atm}##. Why? Is it because, whenever we apply Bernoulli's equation, we should use the pressure (of the air) on the water pushing towards the inside of the drain instead of the liquid pressure exerted towards the outside of the drain by the water on the air?
Thanks!