I'm trying to solve this task:
Where I have to find v1, the velocity at the exit point of the hole.
I know I can use Bernoulli's equation. My question is what should I consider to be the pressures. I was thikning of writing the equation like this:
$$P_0 + \frac12 \rho v_1^2 = P + \frac12 \rho v_2^2$$
Why do they add the terms with $y_2$ and $y_1$? I would have thought that $\rho g y_2$ is the pressure in the bottom, not in the surface. And doesn't the pressure in point 1 have to be simply the atmospheric pressure, $P_0$?