MODEL: The pressure at any point in the fluid depends only on the depth of the point and the density of the fluid above (equation 13.9, pg 442). We can calculate the pressure at the bottom of the U-tube (at the junction of the two fluids) by using either arm of the tube.
SETUP: On the left hand side, what are the appropriate values of density and depth d? What are the values on the right hand side? Does the value of P0 matter?
SOLVE: Set the value of P at the bottom calculated in the left hand tube equal to the value calculated in the right hand tube.

© 1997 Susan M. Lea