- #1
ChickysPusss
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Homework Statement
Water is coming out of a water cannon at 25m/s, what is the pressure inside the cannon?
Homework Equations
Bernoulli's (modifiedd): v = √(2gh) -> h = v^2/2g
Prssure(liquid) : P = ρgh
The Attempt at a Solution
Well, I wasn't too sure how a water cannon works, so I "made one" that is just a giant vat with a lot of water, and a hole at the bottom.
I figured that for the water to come out at 25m/s, the height would have to be ~31m.
h = (25^2)/2g
So then I said, Pressure must be equal to ρgh, which is 1000 * 9.8 * 31m = 303,800Pa
But the answer the book gives says its "4.125 x 10^5 Pa absolute."
Any idea why my solution is incorrect?