# Fluids straw problem

## Homework Statement

This problem pertains to the drinking straw trick. You decide to place your finger over a 20.0cm straw. 95.0% of the straw is filled with water, while the top is full of air. Treating the straw as an ideal gas, compute fraction of the straw that is filled with water when the straw is drawn out of the glass.

## Homework Equations

$$B = \rho gV$$
$$P_1 + \frac{1}{2}\rho v_1^2 + \rho g h_1 = P_2 + \frac{1}{2}\rho v_2^2 + \rho g h_2$$

## The Attempt at a Solution

I am not really sure how to start this, but I am pretty sure I have to do something with the pressure of the straw. The atmospheric pressure is equal to 101325 Pa, and the pressure at the bottom of the straw should be Patm + rho*g*h, so there is a pressure differential. If 95% of the straw is filled with water, does that mean that the water contributes to 95% of the buoyant force of the straw while air contributes 5%? I have these ideas but I am not too sure how to apply them to proceed with this problem